Image customization specifications in VirtualCenter must have a NIC configured in order to create a desktop pool.
Details
If a customization specification is present on the VirtualCenter server and it does not have at least one NIC configured , a null pointer exception is generated. This is true whether VDM uses the customization specification or not.
Solution
Configure at least one NIC for all customization specifications present on VirtualCenter servers used by VDM.
This issue is fixed in VDM versions 2.1.1 and higher.