Spamassassin plugin: Can't call method ... on an undefined value (6 messages)

Hoi,

I'm using qpsmtpd and am quite happy with it. Now I encountered
a problem, when someone sent a message with an (as the sender
said) empty body to me.

This is the relevant part of the logfile:

Thu Jul 21 17:51:45 2016 quagga[18965]: 250 <foo@openmailbox.org>, sender OK - how exciting to get mail from you!
Thu Jul 21 17:51:45 2016 quagga[18965]: dispatching RCPT TO:<bar@marmaro.de>
Thu Jul 21 17:51:45 2016 quagga[18965]: 250 <bar@marmaro.de>, recipient ok
Thu Jul 21 17:51:45 2016 quagga[18965]: dispatching DATA
Thu Jul 21 17:51:45 2016 quagga[18965]: 354 go ahead
Thu Jul 21 17:51:45 2016 quagga[18965]: FATAL PLUGIN ERROR [spamassassin]: Can't call method "as_string" on an undefined value at /usr/share/qpsmtpd/plugins/spamassassin line 163.

Thu Jul 21 17:51:45 2016 quagga[18965]: FATAL PLUGIN ERROR [spamassassin]: Can't call method "get" on an undefined value at /usr/share/qpsmtpd/plugins/spamassassin line 257.

Thu Jul 21 17:51:45 2016 quagga[18965]: FATAL PLUGIN ERROR [spamassassin]: Can't call method "get" on an undefined value at /usr/share/qpsmtpd/plugins/spamassassin line 257.

Thu Jul 21 17:51:45 2016 quagga[18965]: forwarding to localhost:25
Thu Jul 21 17:51:45 2016 quagga[18965]: FATAL PLUGIN ERROR [queue::smtp_2dforward]: Can't call method "as_string" on an undefined value at /usr/share/qpsmtpd/plugins/queue/smtp-forward line 60.

Thu Jul 21 17:51:45 2016 quagga[18965]: 451 Queuing declined or disabled; try again later
Thu Jul 21 17:51:45 2016 quagga[18965]: dispatching QUIT
Thu Jul 21 17:51:45 2016 quagga[18965]: 221 quagga closing connection. Have a wonderful day.


I'm using qpsmtpd from the Debian package version 0.84-9.

The spamassassin line in the plugins file reads:

spamassassin munge_subject_threshold 8 reject_threshold 12 leave_old_headers rename


Is this a known problem? How can I solve it?

Help is appreciated.


meillo


P.S.
Thanks for developing qpsmtpd, which I think is great software!