[Storm16]

Found a post on the amavis mailing list from March 2006

Net::Server 0.91 (or later) introduced a change which makes
it incompatible with amavisd-new-2.3.3 (or earlier).

Either switch Net::Server back to 0.90,
or try the:
http://www.ijs.si/software/amavisd/a...4.0-rc3.tar.gz

Not sure what version of amavisd ships with Zimbra 4.0.3, so I installed the libnet-server-perl from stable, which is 0.87-3sarge1...I am still getting the " parts_decode_ext FAILED: Error reading from file(1) utility: Bad file descriptor at (eval 51) line 151, <GEN9> line 1" errors.