Bruce,
I think you said that you were using NT Servers, but if your using Novell servers check out this KB on "Error Reading File"

http://support.novell.com/cgi-bin/search/search.pl?database_name=tid&type=HTML&docid=%039F49420%3a957464134%3a%20%28%20error%20reading%20file%20AND%20%22%7bc31w95%7d%22%20%29%20%20%07%01%00&byte_count=3506

It seems to suggest that Error Reading File is caused by the client. As we've seen it, Error Reading File and Invalid Seek Offset seem to be related in that they are the two reacurring untraceable errors.

Well... back to the ISO search