I have a brand new 1.4.5 install of Zabbix running on Ubuntu Server. One of the challenges I'm facing is that some items show up randomly as being "Not Supported by Zabbix Agent" in the GUI and that data can't be displayed. When checking the logs of the Zabbix Agent on the affected box, however, I can see that the values are being polled and data is being gathered. Typically, I can deactivate the Item and then reactivate it and Zabbix will start monitoring it again, however, usually I'll find that several other items, which were previously working, now become "not supported".