Thread:Project:Support desk/MediaWiki won't upload a picture

Situation: When I try to upload a picture, the page loads (as if it where uploading) but after that nothing happens and the page Special:Upload loads again (blank). No error message, no uploaded picture, nothing. I have rights to upload, I've uploaded a lot of images just a couple of weeks ago, I don't know how to solve this.

I'm using MediaWiki 1.18.1, PHP 5.3 and MySQL

Thanks!