Not able to monitor workstations

Hi There -

I am unable to monitor workstations on my networks.  SNMP trap is disabled, however WMI is not picking up.  Is there something I need double check on the workstations to make sure ipMon is able to communicate with them?  My servers are showing up and are being monitored with no problems, just the workstations are giving me grief.  Any ideas?

 FYI - Discovery finds the workstations, just can not report anything back.

Update - Our reverse DNS is horrible.  Replaced hostname with ip address, now can ping the workstations, however can not monitor hard drives.  The error comes up as no disk drives available?  Any ideas?