We are having a awkward problem at the moment..
Seems like we succeeded installing the mod twice?
Now we have to push F5 on every webpage to get the page visible (if not, we just get a blank screen), so our installation has become quite inusable

Our error log shows the following:
[Sun Jan 19 10:55:12 2014] [error] PHP Fatal error: Call to undefined function user_group_forums_unsubscribe() in /httpdocs/forum/includes/functions_user.php on line 2938, referer: /forum/adm/index.php?sid=bfd775c5a44b94f7e597efbbdfc8c860&i=24
I've installed AutoMod hoping it could uninstall the old version, but that wasn't the case.
PS, the old installations were made around 2 years ago, updated PHPbb to 3.0.12 now.
How can I delete the old verion(s), so I can install a fresh MOD?