tar dies on making tape backup

[Jaime]

	I'm attempting to use tar to feed my filesystem(s) to a DLT tape  
drive.  I've done this with FreeBSD 3 through 5 and DAT (DDS-3 and  
DDS-4) tapes for years.  The command now appears to work for a while  
and then dies with this message about 2.5 hours into the process:

archive_write_pax_header: 'x' header failed?!  This can't happen.

	Any idea what this means?

	I'm using:
$ uname -a
FreeBSD atlas.cairodurham.org 6.1-STABLE FreeBSD 6.1-STABLE #0: Wed  
Jun 28 11:27:09 EDT 2006     root at atlas.cairodurham.org:/usr/obj/usr/ 
src/sys/SMP  i386

	This is my first FreeBSD 6.x system, my first SMP kernel, and my  
first DLT drive on a FreeBSD system.  Using Google, I couldn't find  
any answers that were useful.  (Just a few dead threads from various  
forums and mailing lists.)

							Thanks in advance,
							Jaime