vbb Rules Agree button failure

Well i havent edited register.php or signupadult [template] but when someone accesses the 'Rules' page at the start of registration they're given 'Accept/Cancel' and when you choose 'Accept', you're redirected to member.php [comes up blank]. After some testing I find that it should be redirecting to register.php?action=register Why would this be happening? I recentely made the upgrade from 2.2.9 to 2.3.0.