One odd thing is that when I was checking the DB for my RP 1.0.2, it has tables called "rp_usergroups" AND "usergroups".
"rp_usergroups" is empty, and "usergroups" is not. Perhaps "usergroups" is somehow imported into the DB when you choose to use a forum usergroup list.
But, there is not a "rp_stylesheet" table in either my 1.0.2 or newly installed and working 2.9.1 versions. (See the MySQL error involving "rp_stylesheets" in an earlier post).