I'm almost certain that you are using NT 4, then.
There is a well known bug in the CDFS device driver in all the SP revisions of NT 4 (Workstation - I am not sure about Server). It has not been corrected by M$, even though it is documented on the Knowledge Base (don't know the number any more, I'm afraid, this is from memory).
This directly affects Audio Catalyst since the RIPper uses the underlying file system driver to access and manage the disk and the drive. There are various replacements for the driver avaialble, apparently. I have not tried these, and I also have no further info about where they are available/what they are called since I have not had contact with the guy who told me this for a while.
The quick fix is to use a 9X based platform for AC rips instead of NT, which does not have the FS bug. I have no idea if this has been fixed under W2K.
One of the few remaining Mk1 owners...
#00015