Binary package hint: amavisd-new
The command /etc/init.d/amavis force-reload seems to crash amavis. It works fine in older Ubuntu releases, but in Natty, there seems to be some timing problem:
Mar 9 11:45:50 myhost amavis: starting. /usr/sbin/amavisd-new at myhost.alkernetz amavisd-new-2.6.4 (20090625), Unicode aware, LANG="de_DE.UTF-8"
Mar 9 11:45:50 myhost amavis: Perl version 5.010001
Mar 9 11:45:50 myhost amavis: (!)Net::Server: 2011/03/09-11:45:50 Can't connect to TCP port 10024 on 127.0.0.1 [Die Adresse wird bereits verwendet]\n at line 88 in file /usr/share/perl5/Net/Server/Proto/TCP.pm
The message means "Address already in use". It seems as if amavis does not shut down properly before restarting, then the socket cannot be used, and then the old instance dies.