I can't upload anything.

[14:34:13] 550 Can't check for file existence
[14:34:14] 553-Can't open that file: Permission denied
[14:34:14] 553 Rename/move failure: No such file or directory
[14:34:14] Transfer failed.

A couple days ago, I updated my website. I added new menus, pages, and graphics. Today when I went to my website and logged into my FTP, all the changes that were made to any files were reverted back to old versions, and new pages and images I uploaded were completely deleted. Even my index page and CSS sheets was changed back to an old version from a week ago. Now, I can't rewrite over my index page or any other page for that matter, and I can't upload new files. This is seriously screwed up, all progress I made on my site is gone. Rawr.

Hi, check that the owner and the group are correct, maybe some webserver thing has changed that and because that you can't access to then now. (to know that, upload a no existing file and look the owner number and group and compare it with another file).