outbound mail failure - need to fix asap

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outbound mail failure - need to fix asap
\ Vizion (11 Apr 2007)
. \ Vizion (11 Apr 2007)
. . \ (Wietse Venema) (11 Apr 2007)
. \ (Wietse Venema) (11 Apr 2007)

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Subject:	outbound mail failure - need to fix asap
Group:	Postfix-users
From:	Vizion
Date:	11 Apr 2007

Lines such as the the following have suddenly started to appear in maillog accompanied by a failure of the outgoing mail system:

"postfix/sendmail[50035]: fatal: recipient addrresses must be specified on the command line or via the -t option"

System is freebsd 6.1

I have tried
#postmap /usr/local/etc/postfix/virtual
followed by
#postfix reload
but problem remains. It may help to know
#pkg_info |grep mail
cclient-2004g.1 Mark Crispin's C-client mail access routines
imap-uw-2004g_1.1 University of washington IMAP4rev1/POP2/POP3 mailservers
postfix-2.4.0,1 A secure alternative to widely used sendmail

Can anyone put me on the right track to trace this problem?

Incoming mail is working.. but no outgoing.
Thanks in advance
david