Well I've just gone over the steps for the 3rd time and I'm done going over them. I've installed many hacks successfully before so I know I'm not totally incompetent. 1) The options don't appear in the admin panel (under usergroups) and 2) in the User CP when you click the link to upload your signature it takes me to a blank page.
I'm running version 3.0.6 and I've gone through every page of this thread, including the link to the forum where the coder of this hack gives support but has a message saying he's having issues and won't be around for a while.
If anyone has any ideas please share. But I think I'll try installing another one, preferably one that works.