This is as simple as it gets. My school provides us with a personal storage that can be used for a webpage. Its the standard http://www.example.com/~studentname type deal. Previously, I would make changes to an index.html file and upload in using the 'Secure File Transfer Client' to my public_html folder. I'd hit refresh, and bingo.
I used ssh to login remotely edited the .html file with pico, and saved it. if I do a cat on the file after closing it, it's still there. But my neither firefox nor google chrome reflect the recent changes. I've even deleted my cache to no avail.
I've definitely run into cases where even after refreshing my browser cache and any other cache I had control over there was still an external proxy or server-side cache that couldn't be forcibly refreshed. In that case renaming the file should at least get you a current version. If that fixes it, that's the problem.
The only other time I've had this problem was in a situation where files were checked out from their editable location to their final served location via a post-commit hook, and that script broke. But that's pretty much definitely not the case for you. I'm just throwing it out there as another bizarre scenario that I know I wouldn't have thought of if it hadn't happened.