Just an update to this...

I upgraded the firmware on the SCSI RAID controller to version 413O-A09 as found at this link: http://support.dell.com/support/downloads/format.aspx?c=us&cs=04&l=e... bsd&SystemID=PWE_PNT_XEO_1750&os=LE30&osl=en&deviceid=2608&devlib=35&cat egory=35&releaseid=R85295

Since upgrading the firmware we have had no more kernel panic problems.

Thanks to everyone for your help, and thanks to Johnny Hughes for providing the easy links to the firmware.

Bob.