Im am having the same problem in dreamweaver cs5.5. please need help
If the timestamp has changed, then the file has been properly uploaded. You must be looking at a stale page in the browser. Dump your local browser cache and try again.
I have run into something similar on our webserver where the server was caching files. I am not sure how our IT guy fixed it, but I cleared the browser cache, and it still rendered the old page because the server was caching it.
Yes - server caching would be another reason for this to happen. Thanks for mentioning it.
The only way to know for sure about that is to ask the host....