[Mimedefang] Strange "no spaces found" error

[Cormack, Ken]

Has anyone ever seen the following in their logs?

Aug  8 10:46:50 mail01 mimedefang-multiplexor[17118]: Slave 22 stderr:  no
spaces found
Aug  8 10:46:52 mail01 mimedefang-multiplexor[17118]: Slave 22 stderr:  no
spaces found # Warning: non-positive median line gap of 0

I've been seeing either of these two errors in my logs for the last few
days, and cant find a cause.  I don't know exactly when these started
appearing, since I only keep 6 days logfile history on the machines.

I've grepped the source code for both MIMEDefang 2.57 and SpamAssassin
3.1.4, and cant find any reference to "no spaces found".

Anyone ever seen this before?

Ken