setting File permissions

We have somehow managed to create a situation in which I am unable to ftp my changes to the server. The person who set up the site with templates does not know what he may have done to prevent me from being able to edit the files. I can send new files, but am unable to make any changes to existing files. Does anyone know what he may have done that we can correct. He has already eliminated the desing notes, but that did not help.

Thanks