I'm in a very very strange situtation.
I use FileZilla for Windows 7, and when I upload a file to my server I receive: "File transfer successful, transferred 14,939 bytes in 1 second", but when I go to my website to see the changes, nothing is changed.
When I try to upload the file again (overwrite it) I noticed that the files have different sizes, like it was not uploaded.
I've tried this also on other servers and I have the same problem.