When testing a Windows system, you see high end ports usage.
For example, on Windows 2003 (ports 1025 - 5000) or on Windows 2008/2012 (ports 49152 - 65535).
When adding a Windows system, if the "Computer Name" field is not filled in, TPAM will connect the server using WMI to determine the computer's name. WMI uses RPC ports to determine this.
Ensure the "Computer Name" in "System | Details | Information" field has been filled in for all managed Windows systems, this will ensure the WMI calls are not made when using "Test System". Enter the NETBIOS name in UPPERCASE.
Configure the firewall on the managed system to allow these ports.
Refer to Microsoft KBs below for more information on the Dynamic Port Range:
Service overview and network port requirements for the Windows Server system
How to configure RPC dynamic port allocation to work with firewalls
The default dynamic port range for TCP/IP has changed in Windows Vista and in Windows Server 2008