I have tested this on my computer and there is no problem on my system.
I had a song playing, it was about 20 seconds into the Song, then I started the Import of a CDG disc as you would when a singer brings a disc in by clicking the CDG button, typing in the Track number, Singers name and Song title. I had no audio drop outs at all.
I was using version 3.303 with a Pioneer Laptop DVR-K05 drive Firmware Version 1.03.
What firmware does your drive have? Here is the Link to the latest firmware update for your Plextor Premium drive:
http://www.plextor.com/english/suppo...m_Premium.html