phpbb/Dolphin intergration issue

Hi I have a question I have a phpbb forum and have 223 members then i wanted to use dolphin 6.1 when i created the dolphin I used the same database info I did with my phpbb now everything is intergrated but my problem is my current members can not log in to the dolphin site using there current user name and password then had with the phpbb but a new member can sign up and there new user name and password can be used in phpbb how can I fix this issue