Thread:Project:Support desk/Strange Error while doing basic editing/reply (3)

You have currently installed InputBox, New Page CSS and ParserFunctions. Yes, you can try without them (although I don't know if that helps). But try it.

I noticed one thing else: In your installation $wgArticlePath and $wgScriptPath point to the same path. This is not recommended and can cause problems. Try changing one of them, e.g. move the files and folders of the wiki into the subfolder media/w/ (which you have to create first) and then set that one as $wgScriptPath.