Thread:Project:Forum/Warning: mkdir() function.mkdir : Permission denied/reply (2)

I know I am late but it can be useful for others, as it took me a while to find out what my problem was. So... if you ever have this problem while uploading files to your mediawiki and your Linux system is running SElinux, that may be the source of your trouble. Check this page for a protential solution. It worked for me.