> Here's the portion of the file sendsize.20030416004501.debug
> pertaining to www:sda8 which ran last night: [...]
> runtar: error [must be invoked by backup]

OK, so that is certainly the root of evil.  Now to find out why it isn't
called with whatever ID it needs; as Joshua pointed out, check your
runtar permissions and owner, and your invocation from xinetd or inetd. 
You didn't happen to do a tiny change there recently, or install a new
amanda version where you could have forgotten to give the same
`--with-user' option as before?

Alex

-- 
Alexander Jolk         /         BUF Compagnie
tel +33-1 42 68 18 28 /  fax +33-1 42 68 18 29