It seems to me like the maintainence script does not create the needed database table? If that is the case, it would be nice with a line or two about how the table should be set up. rotsee (talk) 20:00, 19 February 2012 (UTC)
Topic on Extension talk:ShortUrl
in case someone else is looking, it's all in the folder ”schemas”. I somehow didn't notice that.
You can also run the mediawiki maintenance script. I have updated the documentation - https://www.mediawiki.org/wiki/Extension:ShortUrl#Installation
Even easier... Thanks! It's working really great, I even wrote a short blog post about it: http://blog.xn--ssongsmat-v2a.nu/2012/02/20/creating-a-url-shortener-with-mediawiki/