Help me please!!

[hi5]

Ok, I have phpbb 2.016 and joomla that comes with cpanel fantastico.

When people register they get an error message when they submit registration:
Could not insert data into ACL table

DEBUG MODE

SQL Error : 1062 Duplicate entry '18--0' for key 1

INSERT INTO jos_core_acl_groups_aro_map VALUES(18, '', 0)

Line : 726
File : usercp_register.php

It does still register them but they think they aren't because of the error. I am sure it is probably because i do not have the right bridge. The login mod i installed was for all registrations to go through phpbb..

Any help would be appreciated.
The site is www.supplyshare.com

Thanks