Mbox mini 2 makes my Mac crash?

[ReB87]

I have a Mbox mini 2 for about 2 weeks now. In this time my Imac (Core 2 Duo alu) has gone from a very stable workhorse to a Mac that crashes all the time.

I've already reinstalled the whole Mac, but that didnt help. The crashes occur mostly in Itunes and the webbrowser (when playing sound). The program stops respondig, and when i force quit it, its still active in the dock and every other program crashes too. When trying to shutdown the Mac, it hangs on the shutdown process leaving the indicator active.

I have no clue what could be wrong. This is a fresh 10.5.7 install with only "Pro_Tools_Le_v8_56245.dmg" installed (nothing else!!). When I go to my Imac's preferences and click "Digidesign Mbox 2" it says "Firmware version 1.40". Is this the newest firmware? Or are there any updates that I could try?

What could this be? I'm very happy with the Mbox, but the instability does not make me happy.