You said "I can successfully use Barcode Scan", but the output does
not show any barcode style labels.
Have you checked the tapes in the library have barcodes installed on them ?
Another idea
You should be able to test the library outside of DP using LTT (Library
and Tape Tools). I think LTT is downloadable from www.hp.com (search the site for "library and tape tools").
If you need help with LTT try to find an MSL forum to ask.
All the best, Stewart