So, i have been trying to get 4 players active on rockband. I’ve hooked up two guitars, one guitar from the rockband package and another guitar from the game guitar hero, but it wont let me play as the bass player when i am trying to have four players.

If you are using an XBOX 360 then it might be a cable issue. However if you are on he PS3 then you are outta luck. The Guitar Hero controller for the PS3 is not compatible with RockBand.