MediaWiki: Problem uploading images and files
 

I installed mediawiki on mandriva 2008 from the repository.
Did all the configurations in localsettings.php regarding fileand image uploading. But still when i upload an image or file(even as small as 20 kb)
and when i click enter after uploading the image or file....It shows a blank page.
I dont know whats the problem , i also changed php.conf to accept upto 90mb,,,but still this problem????
Pls if anybody got a solution???