firewire problems

[bickele]

I've been using two firewire HDs (EZQuest Cobra and ONE Technology Flyhigh) for backups because I couldn't record on them using PT (error -9060).
I upgraded OS 9.0.4 to 9.1 as suggested by the dealer I bought them from.
Now I get 24 tracks recording/playback from the firewire drives but if I try to copy files bigger than a few MB from one of the SCSI drives to the FW the computer crashes a few seconds after the "copying" window opens.

The temporary solution I figured out is to keep the OS 9.1 in the internal drive and an OS 9.0.4 in one of the external SCSI drives and start the Mac from the first if I need to record to the FW HDs or from the second if I need to use the FW drives for backups.

Can anybody help?

What extensions are needed for FW to work properly? I tried several drivers and I have many firewire extensions in the system folder but most of them are inactive...

thanks
b.