Dp Works, Cubase Doesn't- Why? Options

[tieitdown]

Hi to the M & M world here... I've tried my best to figure this out but have just hit a wall with ideas.

I've got a G4 500 Powerbook with 1gb of ram. I'm using a Tascam US 122 which seems to work perfectly fine with DP 4.1 but using Cubase SX 1.06 I think, I've got problems. With DP I can record an audio track and listen to it thru headphones run thru the Tascam. WITH CUBASE I hear an echo in the headphones recording audio and the computer stubbornly wants to send the audio out through the Powerbook speakers, at a much lower volume. So recording with Cubase it echos into my headphones, just slightly and I don't hear a thing in the phones when I press "play." WHY IS THIS?

I can barely hear that it is recording but why is the audio play not going thru the headphones? And the echo? Why does it work with DP fine but not Cubase, I'm wondering where a preference is that I've missed, I've looked all over.

Any ideas?