5.1_RC2 panics during install on indy

Hi,

I thought I'd give 5.1_RC2 a try on my Indy but I haven't been able to
complete the install, I get the same panic at different points each
time I try it:

wdsc0: TAG reselect without IDENTIFY; MSG 0; sending DEVICE RESET
wdsc0: TAG reselect without IDENTIFY; MSG 0; sending DEVICE RESET
panic: MSGOUT with no nexus
Stopped in pid 0.2 (system) at  0x882dbfa4:     jr      ra
                bdslot: nop 
db> bt 
0+882dbfa4 (97ffe000,d,0,cba03d74) ra 0 sz 0
User-level: pid 0.2
db>

My Indy is a 150MHz R5000SC model with 256Mb RAM and the disk is a 4.3GB
IBM DCAS-34330. Does this look like a disk error or a kernel problem?

George