broken header ?

been getting this error
for emails from a particular client
according to them email bounces off us
but goes to every one else who is CC'd outside our company.
i've seen that MIME::paerser error
coulde be caused by ripOLE but it is desaibled.

any help would be apritiated

May 18 04:33:29 <server> amavis[86543]: (86543-06) WARN: MIME::Parser
error: unexpected end of header
May 18 04:33:36 <server> postfix/pipe[86696]: BA8A7C94C4:
to=<user1@server.com>, relay=cyrus, delay=0, status=bounced (data
format error. Command output: user1: Message contains invalid header )
May 18 04:34:11 <server> amavis[86731]: (86731-02) WARN: MIME::Parser
error: unexpected end of header
May 18 04:34:14 <server> postfix/pipe[86696]: 8BCB3C94EC:
to=<user2@server.com>, relay=cyrus, delay=0, status=bounced (data
format error. Command output: user2: Message contains invalid header )


thanks
stas