Error: EXT3-fs error (device sda3) in start_transaction: Journal has aborted

[Shane Presley]

Hello,

I'm having a problem with a RHEL4 system on a 1650.  The system will
boot fine, run fine for a couple days.  Then it crashes, logging lots
of these messages to syslog...

Oct 27 07:15:02 myserver kernel: EXT3-fs error (device sda3) in
start_transaction: Journal has aborted
Oct 27 07:15:32 myserver kernel: scsi0 (1:0): rejecting I/O to offline device

It marks / as read-only, and of course the system grinds to a halt. 
To me this sounds like a hardware (disk or raid?) problem, but I
wasn't sure if there was anything else I should look at first?

This happens about once a week.
Thanks
Shane