tw_cli reports not configured

[Stephen Borrill <netbsd%precedence.co.uk@localhost>]

I have a machine with a 3ware RAID card:
twe0 at pci3 dev 11 function 0: 3ware Escalade
twe0: interrupting at ioapic0 pin 23
twe0: 8 ports, Firmware FE8S 1.05.00.068, BIOS BE7X 1.08.00.048
twe0: Monitor ME7X 1.01.00.040, PCB Rev5    , Achip 3.20    , Pchip 
1.30-66
twe0: port 0: ST3400832AS                              381554 MB
twe0: port 1: ST3400832AS                              381554 MB
twe0: port 2: ST3400832AS                              381554 MB
twe0: port 3: ST3400832AS                              381554 MB
twe0: port 4: ST3400832AS                              381554 MB
ld0 at twe0 unit 0: 64K stripe RAID5, status: Normal
ld0: 1490 GB, 194564 cyl, 255 head, 63 sec, 512 bytes/sect x 3125682688 
sectors

I've been using the FreeBSD binary tw_cli for a number of years. This 
machine is running 5.1_STABLE from July-ish.  I'm sure when I was running 
an earlier netbsd-5 version it worked fine.

backup 1# tw_cli rescan

(0x08:0x0006): (0x08:0x0006): Device not configured

Segmentation fault (core dumped)

ktrace shows a number of these:
 11741      1 tw_cli   CALL  open(0xbfbfd540,2,0xbfbfd948)
 11741      1 tw_cli   NAMI  "/emul/freebsd/dev/twe0"
 11741      1 tw_cli   NAMI  "/dev/twe0"
 11741      1 tw_cli   RET   open -1 errno 6 Device not configured

--
Stephen