redember

Motu 828 Highpitchsound/driver Not Found

Hi i noticed there was a similar problem brought up in the past... but i'm hoping there maybe some updates....
i run logic 6.4.3 on G5 macosx 10.3.4 with a motu 828 (not mkII) with the latest driver dowloaded from their site.

all of a sudden one nite i got "core audio selected driver not found (-10202)" - ive reinstalled logic+the 6.4.3 update+the motu driver nothing worked. the next morning everything is as it has been for years but after few hours this highpitched sound cuts in from the motu hardware and the driver is 'not found' again and core audio is not functioning.
this has happened a few days running now. just now it appears that if i powerdown everything for longer than, say, 20 minutes its all working again until a few hours after that the highpitch sound thing again.

(this maybe just a coincendence-- but it first happened shortly after a NI guitar rig2 demo version ran out (with no warning-just loaded up a song and "guitar rig2 not found" came up - i tried to re-load the demo version which was probably dumb - but i didn't expect major repercussions from doing that) could this have caused a bug? i have since ordered the real version in the hope it might fix things.
i'm now thinking the motu828 has got some kind of erratic problem and needs to be replaced?

hope someone can help, i am totally freakin out as i have just stared a business doing advertising music and the deadline's are sooo tite!
regards,
Ewan