I notice this thread has had no reply so I'll throw an idea at you.
I understand that there are TWO*items that may need to be installed to print to a Lightscribe:
Simple Labeller (which you have)
the "host" program available from http://www.lacie.com/support/drivers...r.htm?id=10095
. You will be dealing with an RPM file.
See if this helps.