Not Connected. What Is Wrong?

Hi all. I have a really dumb question. I use a Digi 002 rack, and Mac OSX 10.4.6 running on a PowerBookG4. When I open the CoreAudio Manager to connect the Digi rack it says in the Status: Not Connected (HW in use). The rack is connected to the computer via firewire and the unit is on. I'm not running any other applications. What could possibly be wrong?

Please start with the steps in the sticky at the top of this forum, specifically those areas on trashing preference and database files.

i also have an 002 rack, powerbook g4 and osx 10.4.6. the rack won't connect. tried all that trouble shooting nonsense to no avail. tried different cables...etc... the firewire light on the back of the rack constantly flashes green...dont know if it should be solid green? any help? ideas?