Hi,
This problem has been seen before in a windows 2000 system when looking at the Event View. It is an Error 18. You did not provide much information, so it is hard to tell exactly what is going on. Have you tried out the card? In the case of this previous report, the card still worked. The workaround is to create the following key in the registry using regedit:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\niserial\Parameters
Hope this helps out.
Aaron K.
Application Engineer
National Instruments