SATA raid problem hardware or ???

Mac G5 (dual 2.5 - OS 10.4.9) gave a system msg re. Device Removal
error & the icons for my SATA raid disappeared from the desktop. were
gone. The raid enclosure is much like this...
http://www.sonnettech.com/product/fusion500p.html

A new port-multiplier raid enclosure mounted the raid volumes (5x
Hitachi 500gig) twice out of the box but then stopped working. I'm
trying to nail if this is a hardware issue or somehting else.

If the stripe became corrupt on the sata raid would that cause the
system not to "see" the hardware? That is - (in Disk Utility for
example) - not see "hardware" name of the physical drive like
"Hitachi ###" above the familiar desktop name of the volume. I could
understand the names of the striped volumes not appearing but not
seeing the hardware would seem to point to hardware failure and not to
a corrupt stripe or data, yes?

Thanks,

Paul

p.s. I'm having Sonnet look at the sata card - Tempo Sata x4p for PCI-
X

this is what the console says...

running!!!
Oct 28 20:47:45 Pauls-G5 kernel[0]: SonnetSATA::mv (ERROR) SStatus
0x00000000:
Oct 28 20:47:45 Pauls-G5 kernel[0]: SonnetSATA::mv (ERROR) SControl
0x00000300:
Oct 28 20:47:45 Pauls-G5 kernel[0]: SonnetSATA::mv (ERROR) SError
0x00000000:
Oct 28 20:47:45 Pauls-G5 kernel[0]: SonnetSATA::mv (ERROR) IF Ctrl
0x00000000: TXPort 0x0
Oct 28 20:47:45 Pauls-G5 kernel[0]: SonnetSATA::mv (ERROR) IF status
0x00804000: RXFIS 0x0 RXPort 0x0
Oct 28 20:47:53 Pauls-G5 kernel[0]: SonnetSATA::sataEventNotify@0
Cable Event Connect
Oct 28 20:47:58 Pauls-G5 kernel[0]: SonnetSATA::mv (FATAL_ERROR) 36880
0: SaDevInterrupt: No command is running!!!