"no such file to load -- my_extensions (MissingSourceFile)"

I have a Rails application runnng on one machien quite happily, using
Ruby 1.9.1-p243 and Rails 2.3.3. I copied the app and config folders to
another machine, on which I'm also running 1.9.1-p243, but via RVM.
Whenever I try to launch the Rails application ('server', 'runner',
'console') I get the error message "no such file to load --
my_extensions (MissingSourceFile)".

Based on one googled suggestion I created a nearly empty file,
$ROOT/config/initializers/my_extensions.rb
but this did not help. I'm also wondering if I need to create a
'wrapper' as I've seen this mentioned int he contect of using Rails and
RVM - but I can't see what I would need to do for, say, 'ruuner'. All
advice gratefully received.

So, really no idea what's going on here, but it sounds like there's a
library of my_extensions.rb someplace that maybe didn't get copied over, or
wasn't bundled correctly? Look through the Gemfile, the Gemfile.lock, the
old installation, etc. Sorry if you've already gone over all that, I just
am taking a shot in the dark.

Post the full error including the stack trace if there is one. First
have a good look at it though to see if it tells you where it is being
included from. Also do a full text search on the original machine
looking for 'my_extensions' and 'MyExtensions' and do a file search
for my_extensions.rb

Colin

Many thanks to you both - indeed, I was being a muppet, and it's exactly
as you suspected, namely I'd forgotten to copy across a file. Grep'ing
for the file name helped me track it down. Thanks again and Merry
Christmas!

FWIW, do yourself a favor and pick a source control system. Deploying apps by copying files WILL bite you (scratch that, HAS bitten you) in unexpected ways.

–Matt Jones