well at least we know the exact cause.
I'm doing this from memory (I'm currently in class paying attention

)
Open vars_config.cgi
There will be indexes for NonCGIPath and CachePath
Make sure that CachePath includes NonCGIPath. If not, add it (replacing your old NonCGIPath)
If the path is already correct, then you've got to make sure that the cache directory was copied over from where it was previously (this is all based on the assumption that files were recently moved)
Technically, there is one easy way to do it, but it involves uploading a blank vars_config.cgi file and going through installation again.
If these instructions were helpful, reply back and I'll try to be more helpful when I have access to my files.