HELP!! Rake aborted! Can't modify frozen hash

Too bad even the trace doesn't say which hash is involved.

Sorry this post is long: am trying to provide enough context to be
meaningful.

Occurs _intermittently_ when rake jobs:work is pulling a command out of
delayed_jobs while my status observer is in the process of parsing a log
file for detailed results of the previous delayed_job denizen. I have
an observer class (in RAILS_ROOT/lib ) which listens for the events,
makes a copy of them and calls the owner class ( in apps/models ) which
then calls on the log parser (also in /lib) to do the actual work.
(Should both of those classes, the observer and the parser be in
app/models?)

Am due to deliver this application in a few days and this is killing it
(and me).

Am using DirectoryWatcher to look for flag files that indicate the start
and finish of the delayed_jobs.
That is started at the end of environment.rb like this:

require 'directory_watcher'
$scriptStatusObserver = ScriptStatusObserver.new
dirToWatch ="#{RAILS_ROOT}/tmp/flags"
$directoryWatcher = DirectoryWatcher.new( dirToWatch )
$directoryWatcher.glob= "*.flg"
$directoryWatcher.interval=(15)
$directoryWatcher.add_observer( $scriptStatusObserver )
$directoryWatcher.persist=("#{RAILS_ROOT}/tmp/flags/dw_state.yml")
$directoryWatcher.start

at_exit { $directoryWatcher.stop }

This code is outside of the run method (btw is that the best place or is
inside the run better?)

Here is the observer:
require 'script_run'

class ScriptStatusObserver

  def initialize
    @rcvdEvents = []
  end

  def update( *events )
    begin
      puts "#{__LINE__.to_s}: ScriptStatusObserver events:
\n"+events.to_yaml
      cnt = 0

      events.each do |e|
        if e.to_s.match(/^\s*added/)
          cnt = cnt + 1
        @rcvdEvents << e
        end
      end

      ScriptRun.new.catch_up( @rcvdEvents ) if cnt > 0

      @rcvdEvents.clear

    rescue
      puts $!
    end

  end
end

Here is ScriptRun (it attaches to an associative table built with
has_many:through)

#require 'observer'

class ScriptRun < ActiveRecord::Base

  set_table_name "scripts_runs"
  belongs_to :script
  belongs_to :run

  def parse( result )
    parser = LogParser.new
    parser.parse(result)
  end

  def catch_up( events )
     events.each do |e|
      typ = e.type
      path = e.path

      thisMatch = path.match(/flags\/(\d+)_(\d+)_([\d\.]+)_(\w+)\.flg/)
      run_id = thisMatch[1]
      script_id = thisMatch[2]
      ts = thisMatch[3]
      status = thisMatch[4]

      if e.to_s.match(/^\s*added/)
        status_update( script_id, run_id, status, ts, path )
      end
    end
  end

  def status_update( script_id, run_id, status, ts, path )

    scriptrun = ScriptRun.find(:first, :conditions => [ "run_id = ? and
script_id = ?", run_id.to_i, script_id.to_i ])

    if scriptrun.kind_of?(ScriptRun)
      currStatus = scriptrun.status
      if not currStatus == 'completed'

        scriptrun.update_attribute(:status, status)

        if status == 'parse'
          flag = File.new(path)
          logSpec = flag.gets
          flag.close

          logName = File.basename(logSpec)
          logPath = logSpec.sub(logName, '')

          logName =~ /^(([\w_]+)_([\w]+)_(\d+))\.log$/
          name = $1
          basename = $2
          runenv = $3
          tsOrPid = $4

          result = Result.new
          result.log_path = logPath
          result.basename = basename
          result.name = name
          result.script_id = script_id.to_i
          result.run_id = run_id.to_i
          if runenv == 'sit'
              runenv = 'SIT3348'
          end
          result.application_environment_id =
                ApplicationEnvironment.find(:first, :conditions => [
"nodename = ?", runenv]).id

          parse(result)

          if run_completed?( run_id )
            myRun = Run.find(run_id.to_i)
            if myRun.kind_of?( Run )
              myRun.update_attribute( :completed, Time.now.to_f )
            end
          end

        end
      end

    else
      puts "#{__LINE__.to_s}: ScriptRun.status_update: ScriptRun not
found for run #{run_id} script #{script_id} ts #{ts.to_s}"
    end

  File.delete(path)

  end

  def run_completed?( id )
    scriptruns = ScriptRun.find(:all, :conditions => [ "run_id = ?",
id.to_i] )
    scriptruns.each do |sr|
      if not sr.status == 'completed'
        return false
      end
    end
    return true
  end
end

LogParser is too long even for this post but it reads the script log and
pulls detailed information (counts and timings) out of the log and
writes to a details table. It also tallies and calculates averages and
rolls those up into summary tables for quicker access from the web
pages.

Here is the error trace:
(don't ask why everything is under my Windows profile. It's a long
story)

Scanner running 1270239731.43
directory_watcher.notify_observers: #<ScriptStatusObserver:0x48ae838
@rcvdEvents
=[#<struct DirectoryWatcher::Event type=:added, path="C:/Documents and
Settings/
pneve/workspace/waftt-0.29/tmp/flags/100039_11_1270236464.921_parse.flg">,
#<str
uct DirectoryWatcher::Event type=:added, path="C:/Documents and
Settings/pneve/w
orkspace/waftt-0.29/tmp/flags/100039_18_1270239550.108_parse.flg">]>
update:[#<struct DirectoryWatcher::Event type=:added, path="C:/Documents
and Set
tings/pneve/workspace/waftt-0.29/tmp/flags/100039_19_1270239727.368_parse.flg">,
#<struct DirectoryWatcher::Event type=:removed, path="C:/Documents and
Settings
/pneve/workspace/waftt-0.29/tmp/flags/100039_18_1270239550.108_parse.flg">]
rake aborted!
can't modify frozen hash
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/rails/activerecord/l
ib/active_record/attribute_methods.rb:313:in `[]='
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/rails/activerecord/l
ib/active_record/attribute_methods.rb:313:in
`write_attribute_without_dirty'
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/rails/activerecord/l
ib/active_record/dirty.rb:139:in `write_attribute'
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/rails/activerecord/l
ib/active_record/attribute_methods.rb:211:in `last_error='
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/plugins/delayed_job/
lib/delayed/worker.rb:141:in `handle_failed_job'
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/plugins/delayed_job/
lib/delayed/worker.rb:115:in `run'
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/plugins/delayed_job/
lib/delayed/worker.rb:162:in `reserve_and_run_one_job'
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/plugins/delayed_job/
lib/delayed/worker.rb:92:in `work_off'
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/plugins/delayed_job/
lib/delayed/worker.rb:91:in `times'
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/plugins/delayed_job/
lib/delayed/worker.rb:91:in `work_off'
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/plugins/delayed_job/
lib/delayed/worker.rb:66:in `start'
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/rails/activesupport/
lib/active_support/core_ext/benchmark.rb:10:in `realtime'
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/plugins/delayed_job/
lib/delayed/worker.rb:65:in `start'
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/plugins/delayed_job/
lib/delayed/worker.rb:62:in `loop'
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/plugins/delayed_job/
lib/delayed/worker.rb:62:in `start'
C:/Documents and
Settings/pneve/workspace/waftt-0.29/vendor/plugins/delayed_job/
lib/delayed/tasks.rb:13
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:636:in `call'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:636:in `execute'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:631:in `each'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:631:in `execute'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:597:in `invoke_with_call_chain'
c:/Documents and Settings/pneve/ruby/lib/ruby/1.8/monitor.rb:242:in
`synchronize
'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:590:in `invoke_with_call_chain'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:583:in `invoke'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:2051:in `invoke_task'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:2029:in `top_level'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:2029:in `each'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:2029:in `top_level'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:2068:in `standard_exception_handling'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:2023:in `top_level'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:2001:in `run'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:2068:in `standard_exception_handling'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.
rb:1998:in `run'
c:/Documents and
Settings/pneve/ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/bin/rake:
31
c:/Documents and Settings/pneve/ruby/bin/rake:16:in `load'
c:/Documents and Settings/pneve/ruby/bin/rake:16