Strange. I sent an email to admin@deadlystream.com about the problem, including screenshots of it, but I guess it hasn't been read. The "Post template" section (which appears to be gone now) contained a single radio button with no text, and whether you checked it or not you got the same error: "The following errors were found: Post Template: Cannot be left blank".
Why is there a download limit at all? There aren't that many files, and if you want some of the other mods, you'll have to wait a couple of days before you can get them all. Is there a purpose, other than preventing new users from trying the software you host right away?