Thread:Project:Support desk/File upload not possible: MIME Type or wrong ZIP detection

Hi! I am new here and this is my first install: http://www.mediawiki.attac.at

I have the following problem: File upload is not working correctly. I get the error that the file ending is not corresponding to MIME but I only try to upload a jpg... If I if I use $wgVerifyMimeType = false; It say that there is a problem with the zip file. So what I thing is that the fil ending or MIME type can not be recognized correctly. Does someone knows about this issue?

mediawiki 1.18. PHP Version 5.3.3-7+squeeze3

Thanks in advance, Thomas