I ran in to a similar problem when I was taking a Perl class a while ago. Sometimes I would be doing my work at work and other times at home, and forget to transfer "the current version" of whatever I was working on. Major pain in the ass.

Now, whatever project I'm working on goes in to an FTP directory so that I can grab the latest version of anything off any machine I'm working on. It does the job for me and I haven't run in to that problem since.

There is no emoticon for what I'm feeling now.