Virus Ti and Logic 6

[bipolar]

I'm sure I've read somewhere that the Virus Ti isn't compatable with Logic 6. Now, so far I've had no problems with it, apart from one small thing. Which is as follows. Let me see if I can make some sense here.

Equipment used - Virus Ti 61, Logic 6, Powerbook G4 1.67 with 2gig ram.

Ok, I like to use 'Drums from Hell' drum software. Whenever I have the drum track highlighted the Virus stutters and almost completely cuts out, leaving just the drums and any audio to be heard. The Virus sounds return when I highlight the virus track again. I have tried this with the virus as the soundcard, and with an edirol firewire soundcard. Same happens.
Is this just how things work, or is something wrong?

Hope this makes sense and someone can shed some light.
Thanks in advance.