Let's start with some basic stuff first, and then we'll get to the nitty gritty.
First, have you measured your excitation voltage to be sure it's active? What are you using for excitation? Keep in mind, the 6033 has no analog outputs.
Second, be sure that your analog inputs are configured for differential so that the negative side of the input is not connected to any ground.
If your bridge is truly a full-bridge (you don't need any resistors to complete the bridge), this *should* be enough.
Let me know, and we'll work it out.
Mark