I do not beleive you did it right because your not throwing errors anywhere else in the program and the members table is valid in Invisionboard. If that table did not exist you would get errors everywhere and not be logged in.
I would think your forum database table prefix you did is wrong. I would think maybe the table prefix is ipb_ not ipb
I can not obviously know without more info. What is under your reviewpost admin for forum settings table prefix of your forum?