Undefined method error when loading schema (Win 7)

I'm trying to run an existing project on a new installation of Rails
on a Windows 7 machine. When I try to load the schema, I get:

rake aborted!
undefined method `full_name' for "\377\376-":String

I can't figure out what is causing the error. My best guess is some
kind of gem conflict, but various reinstallations and copious
experimentation have failed to get to the bottom of it.

I'm running Rails 2.3.5, Ruby 1.8.7, and MySQL 5.0 and installed Ruby
via the one-click installer. Loading the schema on another project was
successful, so it must be something related to my specific project
code, but I can't see what. If anyone can help, I'd be really
grateful.

A trace on schema:load gives:

PS C:\Projects\otwarchive\otwarchive> rake db:schema:load --trace
(in C:/Projects/otwarchive/otwarchive)
** Invoke db:schema:load (first_time)
** Invoke environment (first_time)
** Execute environment
rake aborted!
undefined method `full_name' for "\377\376-":String
C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/rails/
vendor_gem_source_index.rb:
50:in `refresh!'
C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/rails/
vendor_gem_source_index.rb:
45:in `each'
C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/rails/
vendor_gem_source_index.rb:
45:in `refresh!'
C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/rails/
vendor_gem_source_index.rb:
29:in `initialize'
C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/rails/gem_dependency.rb:
21:in `ne
w'
C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/rails/gem_dependency.rb:
21:in `ad
d_frozen_gem_path'
C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/initializer.rb:298:in
`add_gem_lo
ad_paths'
C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/initializer.rb:132:in
`process'
C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/initializer.rb:113:in
`send'
C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/initializer.rb:113:in
`run'
C:/Projects/otwarchive/otwarchive/config/environment.rb:40
C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in
`gem_original_re
quire'
C:/Ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in
`require'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/
dependenci
es.rb:156:in `require'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/
dependenci
es.rb:521:in `new_constants_in'
C:/Ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/
dependenci
es.rb:156:in `require'
C:/Ruby/lib/ruby/gems/1.8/gems/rails-2.3.5/lib/tasks/misc.rake:4
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `call'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `execute'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `each'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `execute'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in
`invoke_with_call_c
hain'
C:/Ruby/lib/ruby/1.8/monitor.rb:242:in `synchronize'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in
`invoke_with_call_c
hain'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:607:in
`invoke_prerequisit
es'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:604:in `each'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:604:in
`invoke_prerequisit
es'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:596:in
`invoke_with_call_c
hain'
C:/Ruby/lib/ruby/1.8/monitor.rb:242:in `synchronize'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in
`invoke_with_call_c
hain'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in `invoke'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in
`invoke_task'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in
`top_level'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in
`top_level'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in
`standard_exceptio
n_handling'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in
`top_level'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in
`standard_exceptio
n_handling'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run'
C:/Ruby/lib/ruby/gems/1.8/gems/rake-0.8.7/bin/rake:31
C:/Ruby/bin/rake:19:in `load'
C:/Ruby/bin/rake:19