DVDFab problem with 2 instances

I am using DVDFab Decryptor v3.0.3.5 and I can’t run two instances anymore. I am ripping two DVDs to dual HDDs - this worked fine with v2.9.8, but stopped working with v3.0. I get the following error:

12:37:36: Task_1 failed! Error=300
12:37:37: Process failed!

Using Athlon64 X2 3800+, XP SP2

Any ideas? Thanks!