fsck failing

[Dudley]

Note: If there's a more appropriate mailing list, please let me know.

I've been running a FreeBSD 4.11 installation for a couple of years without
issue. Unfortunately, one of the drives on the 3Ware Escalada 8500 RAID
array died leaving the array in a degraded state. The drive likely died in
an outage which also corrupted the filesystem. That said, the FreeBSD
install is still able to boot until it attempts to mount the filesystem.

During the boot process, I get the following error:

Can't stat /dev/twed0s1a: Bad file Descriptor
Can't stat /dev/twed0s1a: Bad file Descriptor
/dev/twed0s1a: CAN"T CHECK FILE SYSTEM
/dev/twed0s1a: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY

It drops me in to single user mode allowing me to run fsck. If I run just
fsck then, it runs successfully but doesn't check twed0s1a which means on
reboot the problem is still there. If I force fsck on that partition by
running `fsck /dev/twed0s1a` then I get the same errors as above.

Please let me know what other steps I should take to get the system booting
again.

Thanks in advance,