Anyone else using a Lambda?

I am having a problem i think with the set up.
I get a nasty pulse sound during play back.
I am using WDM driver setting.
I recorded just a short couple of guitar chords then played them back and it sounded bad.
I switched back to my sound blasted audigy2zs and played the file back and it sounded ok.
I am hoping that I just don't have something set right in Sonar and thats my problem.
That is why I am hoping someone that has a Lambda will resond so I can compare notes with them.
I bought the Lambda as a scratch and dent so I still have time to send it back, but hopng it's just a simple case of user error.
Dell Pentium 4 3 ghz, 512 ddr2 Ram, Audigy 2 sound card, xp sp2