Attachment_FU -- stops creating after first file creation

I'm using attachment_fu for award nomination site and I'm running into a very strange problem that I've found absolutely zero information on. When running on our remote server (redhat fedora), I can only upload one file. After the classname/0000/0002 or whatever directory gets created once and the file is upload and written, I cannot seem to write to that directory ever again without deleting it. I don't get an error. I just get returned to the controller index with no uploaded data any time I try to write. The original file that was there remains intact and working until I destroy it (which works). Even after destroying it, I can't create a new file.

Interestingly enough, I don't have this problem at all when running on my local servers (two different macs). Only on the remote server.

Any help, suggestions, links, or just pointing in the right direction is most appreciated.

The theory at the moment is that when attachment_fu creates the classname/0000/0002 directory structure, it perhaps checks to see if it exists first. When it sees that classname/ already exists, the process stops for some reason. Does anyone know where I can find the bit of code in attachment_fu that might decide this?

http://bs.techno-weenie.net/!source/2920/plugins/attachment_fu/lib/technoweenie/attachment_fu/backends/file_system_backend.rb#36

Thanks for the link, Isaac. It's definitely putting me on the right path. Thing is... I'm having a really hard time discerning what exactly it is that this code is doing. Would anyone care to parse some of the logic and syntax for me? I'd greatly appreciate it.