I'm not sure which file it is in, but you need to remove the fields you just deleted from the SQL queries in the code.
So the one above would become:
Code:
SELECT usergroupid,title,usertitle,canview,cansearch,canemail,canpostnew,canreply,canadminedit,canedit,candelete,canopenclose,canmove,cancontrolpanel FROM usergroup WHERE usergroupid=6
That particular one is in the admin/usergroup.php i believe but there will be more instances of it around the rest of the forum.
Hope that helps!