I had a similar problem using a PXI-1010 with a PC, WINDOWS 2000 and LabVIEW 6.1.
The steps that worked for me are the following:
1)Removed the MXI-3 card and its software from the PC.
2)Installed WINDOWS XP professional.
3)Installed LabVIEW 7.0
4)Reinstalled the MXI-3 card and software.
I hope this will give you some ideas.
Scientia est potentia!