Try rebooting the system a couple of times. Installing AV has to remove AV first before it can re-install so it can have multiple steps.
9.6 gets a bit better with this as you gain the ability to install/remove/repair individual modules (do not send the agent again).
Mark McGinn
MarXtar Ltd/MarXtar Corporation
http://landeskone.marxtar.co.uk
LANDESK One Development Partner
The One-Stop Shop for LANDESK Enhancements