From looking at the manual it doesn't appear you can enter your own CD lookup database URL. Since they are out of business, it's possible that whatever service they were using is no longer available or accessible.
You might have to use some other software to rip the CDs and then imports them into Qsonix, if that's possible. The software to do this is free, so it's just going to be some extra work on your part. Or you can continue to enter the data manually - which could get "old".