Having to convert an old MoinMoin? wiki to MediaWiki?, I found precious little that actually worked to make the conversion. So, a page at a time, I did the conversion. Then I saw how the patterns were going, and cut and pasted the text into Emacs, and built a function to automate it. Then I decided that it would take forever to move over 600 pages, so I automated the entire process.
To use this, just find the base name of your MoinMoin? Wiki and the base name of your new MediaWiki? installations, and feed them to mm2mw-wiki. Tested only on Emacs 22, requires at least a url library with the ability to do HTTP POSTs. Check the Messages buffer to see how it did, per page.
My MoinMoin? wiki was v1.2.x, so I have absolutely no idea if it will work on later versions. This might give somebody a good start, though. I don’t claim that it supports everything; it definitely does not handle attachments correctly. There are probably better ways to do everything but I built this in a couple of days from scratch for my own purposes, and if God is good to me I will not have to do it again.
See Lisp:mm2mw.el if you want to try it out. I probably can’t help you if you have problems, but if you can handle Emacs it might be a good place to start.