Hello.  I was seeing the same behavior you guys are under
NetBSD-2.0/i386, including the error messages.  After applying the patches
in kern/26908, I still got the error messages, but the hangs went away.  I
applied the patches in  late November 2004, and things have been very
stable for me since, when previously, I would see hangs about every 40
days.
	According to the bug kern/26908, this patch was committed to the
NetBSD-2 branch, as well as -current, on March 16, 2005.
-Brian