New msmtpq makes gnus unhappy

Hi,

I finally installed the new msmtpq and msmtp-queue scripts in my
/usr/local/bin .

Old msmtpQ and msmtpq: Copyright (C) 2008 Chris Gianniotis
New ones are current.

While gnus has no problem accepting old msmtpQ, I suddenly 
got an error message with the new msmtpq which was like this: 

,----
| error: "Sending...failed to   mail for [ -oi -f my <at> addy.tld -t ] :
| send was successful; mail queue is empty (nothing to send); "
`----

Hu? The error is that everything just worked fine?

So I did some debugging in the relevant function 
message-send-mail-with-sendmail which errors, displaying
"Sending...failed to" and the content of a buffer, given
that this buffer actually had some content.

So I rechecked with the old msmtpQ script and indeed, the buffer is
empty, so no error.

If I understand the elisp correctly, that function simply puts all
output from sendmail-program (i.e. msmtpq) in that buffer and expects 
it to be empty if everything was fine.