Thread:Extension talk:CheckUser/Installing extension breaks other tools

I recently isntalled this on a wiki and CheckUser itself works fine, but when I tried to change someone's user rights, the attempt failed, displaying a completely blank page. I also noticed that attempting to delete and move pages also failed and showed a blank page. I edited local settings to remove the inlcude once line, and the tools that were broken were fixed. I know that this probably isn't enough to diagnose my problem, so is there any way that I can get more detailed information? I'm currently running MediaWiki 1.23.5, PHP 5.6.3-1~dotdeb.1 (fpm-fcgi), and SQL 5.6.21-1~dotdeb.1. Not 100% sure what those mean but I copied it from Special:Version. Thanks for any help you can offer.