I was having a very similar issue with the PB in my 2000 A4 w/ the Symphony HU. I would get the red/green solid about every 3-4 days, and the only solution was to unplug the harness.
I did some troubleshooting and swapped it with the PB unit in my gf's Jetta (Premium IV HU)
The problem persisted, following the PB to the Jetta, though it was worse. It would enter that state almost daily.
I contacted the VW dealer that I bought it from, and they indicated that I could swap the unit basically no-questions-asked. It's been a few days so far with no problems. I think it may have simply been a defective unit.
If you bought the PB from an online VW dealer, you should be able to swap it out under warranty at any VW dealer local to you. If your dealer's not familiar with the PB, this may be more of a hassle, but they're supposed to stand by the product, and since their techs typically know little about the product, their easiest solution is to simply replace it.
Hope that helps ya.
-Steveo