Thanks.
It's the digi003 rack. I can confirm that it works, I've used it to calibrate some outboard gear using just a test tone, and had no problems with routing or the popping clicking issues. It's only with any project much larger, that this issue occurs, and only selected tracks play, with other cutting in and out.
The stand alone driver is this one...
http://avid.force.com/pkb/articles/e...nload/en355067
It is selectable in the device > sounds menu and works with no issues when selected for general pc sounds. I'll get full pc specs to you later on.