As for the rename command you might want to read the FAQ to just registered members!

9. Can I change my files/dirs name in FTP?

No, you can't. Download it, rename and upload.
So you must get ready ahead of time. Because we are using unix systems, so to having sensitive size.

10. Why can't I rename or edit my files on the FTP server?

You can't because all users have a set discreet priviledges, and how the server is set up, users do not have the permissions to do so.

11. Well how do I fix this?

You can't. In order to rename or edit files on your FTP server is to edit them on you computer, delete the old copies on the server, and reupload them to your site.
As regards PHP...how did you get PHP activated in such little time? Did you ask for the upgrade? I need it on my site but haven't yet asked for the upgrade because I haven't posted in the forum as much as needed for that.