What exact error messages are you getting? Sorry, but no one is much help if you don't give us details. *not trying to be rude or anything, by the way >_<*

You should be able to do that, unless your rights to post a server was removed.

Here is step by step tutorial, spoilers because it's some large images.

Goto the Home page, and click on the server tab



Now scroll down a little and click on upload server button



Write information such as ip/hostname and ad a image to get more views, after that click on the save button. And you are done