Errors in admin mail report

[Predatorz]

Hi,

From the admin mail report, on some days i can see a lot of such errors (as below) in the mail report. what causes such error? (Heavy load on MailServer?)


2008-06-20 11:21:13 deferred (host 127.0.0.1[127.0.0.1] said: 451 4.5.0 Error in processing, id=28122-10, parts_decode_ext FAILED: run_command (open pipe): Can't fork at /usr/lib/perl5/5.8.8/i386-linux-thread-multi/IO/File.pm line 192, <GEN19> line 8208. at /opt/zimbra/amavisd/sbin/a 2008-06-20 20:05:57 bounced.

Server running on 2GB RAM, FC5, virtual machine, HA with another same virtual machine.
Release 4.5.5_GA_838.FC5_20070503175107 FC5 FOSS edition

[Predatorz]

This morning the problem happened again.
I stop and start zimbra, and the problem was fixed.
I have search the forums and found that mostly the problem was caused by missing packages.
But my problem is intermittent.