Cause 1:
Here is an excerpt from the agent log:
VERBOSE [IncomingMessage-20] com.quest.glue.core.agent.AgentInstance - Creating agent
INFO [IncomingMessage-20] com.quest.glue.core.agent.AgentInstance - Created agent
ECHO <HostAgents/5.6.4/WindowsAgent/WindowsAgent_on_yourhost.domainname> VERBOSE [IncomingMessage-20] com.quest.glue.core.agent.AgentInstance - Starting data collection
ECHO <HostAgents/5.6.4/WindowsAgent/WindowsAgent_on_yourhost.domainname-agent> INFO [IncomingMessage-20] com.quest.remoteos.SystemMonitorImpl - A host name has not been provided in the agents ASPs, falling back on the agents instance name WindowsAgent_on_yourhost.domainname
ECHO <HostAgents/5.6.4/WindowsAgent/WindowsAgent_on_yourhost.domainname> ERROR [IncomingMessage-20] com.quest.glue.core.agent.AgentInstance - Failed to start data collection
java.lang.NullPointerException
Cause 2:
The AD principle account name cannot be used due to the AD configuration in the environment with different domains.