Hi,
I had similar issue for zenoss-4.2.4 installed on Ubuntu-13.10 via http://hydruid-blog.com/?p=343 procedure.
After small digging if was found that when starting "/etc/init./zenoss start" the script does not call the correct python executable namely /usr/local/zenoss/bin/python but /usr/bin/python which is the standard python for Ubuntu-13.10.
When putting in the path the zenoss python executable this issue disappeared.
#!/usr/bin/env bash
#
# zenoss This shell script takes care of starting and stopping zenmon.
#
# chkconfig: 2345 80 30
# description: Zenoss is a monitoring program written by Zenoss, Inc.
#
##############################################################################
#
# Copyright (C) Zenoss, Inc. 2007, all rights reserved.
#
# This content is made available according to terms specified in
# License.zenoss under the directory where your Zenoss product is installed.
#
#Custom Ubuntu Variables
export ZENHOME=/usr/local/zenoss
export RRDCACHED=/usr/local/zenoss/bin/rrdcached
export PATH="/usr/local/zenoss/bin:$PATH"
#
##############################################################################
set_deamon_list() {
WEBSERVERCTL=$(${ZENHOME}/bin/zenglobalconf -p webserverctl)
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Regards,
Todor