UserParameter not working on zabbix-agent 1.8.1

[sirhopcount]

Hi,

Were experiencing some weird problem with zabbix agent en custom user parameters. We have been running custom parameters for a while with out any problems but recently it stopped working.

We had the following custom parameter:

UserParameter=linux_updates,/usr/lib/update-notifier/apt-check --human-readable|grep "security update"|cut -d " " -f1

But now it returns ZBX_NOTSUPPORTED for some reason:

# zabbix_agent -t linux_updates
linux_updates                                 [m|ZBX_NOTSUPPORTED]

I first thought that there was something wrong with the script or that user permission where wrong but when i run the script as the user zabbix it executes without any problems

# sudo -u zabbix /usr/lib/update-notifier/apt-check --human-readable|grep "security update"|cut -d " " -f1
0

Next i thought that there was something wrong with my zabbix configuration. So i did a brand new install in a virtual machine and i activated one of the example user parameters "system.test"

UserParameter=system.test,who|wc -l

I restarted the zabbix agent and to my surprise this one also failed...

# zabbix_agentd -t system.test
system.test                                   [m|ZBX_NOTSUPPORTED]

This leaves me with no clue what is wrong or how to fix it. Even with the debug level at 4 there is no indicator what is going wrong. I am testing this on a clean ubuntu 10.04 installation with zabbix-agent version 1.8.1

ii  zabbix-agent                    1:1.8.1-1ubuntu1                  network monitoring solution - agent

 zabbix_agentd --version
ZABBIX Agent (daemon) v1.8.1 (revision 9702) (27 January 2010)
Compilation time:  Apr  6 2010 01:54:49

Does anybody have an idea whats wrong or how to debug any further ?