828 mk2 with Mac OSX not working. Clock-issue?

[gakken]

I´m having a problem with mye 828 mk2. It´s really unstable, and what happens almost every time I try to choose the MOTU as my sound-source, is that when I for exemple try to play files in iTunes, the file won´t play, and the samplerate-indicator starts to blink. The system crashes, and I cannot quit or open any programs until I´ve turned off the 828.

Could this be an issue of samplerate? I´ve tried different ones, but can´t find one that´s stable.
Or and Clock-source-problem? I´ve tried internal and SMPTE...

Any suggestions?

I have the newes driver-software, and firmware 1.01. My Mac is a 2.2 GHz Intel Core 2 Duo, with 4 GB RAM, and OSX 5.5.