Some VooDoo with PsShutdown?

[KapaKai5O]

I've been using psshutdown for years. Never came across this problem.
I built a 7Pro system (32bit) but can't for the life of me get it to remotely shutdown systems in the lan.
Can't shutdown, restart, standby, logoff, nada.
It replaced another 7Pro system (Laptop) that worked and still works flawlessly.
Simple batch files: 'psshutdown \\computer name -r -t 10' for restart,
'psshutdown \\computer name -d -t 10 for shutdown etc....
Running the file produces no errors, and the psshutdown service is there correctly.

I can mostly* connect to and from each system (they are older xp & win2003 servers & some win7).
* Every now & then it will not connect to a system yet I can connect from that system to this one.
Very strange. When that happens, I usually end up having to reboot this system to connect again.
It seems intermittent. Otherwise this system is extremely solid.
I've been troubleshooting this for hours and can't figure out what I'm missing.
What should I be looking for?
Any ideas would be a blessing and thanks in advance!

P.S. When the system will not connect to a system, I can still use remote software (like radmin)
and it connects with no issues.

 

[KapaKai5O]

After troubleshooting this more, I'm thinking the 'voodoo' is with Windows OS.
I just now realized I haven't even flushed the dns cache or reset the TCP stack.

It's just I've never seen this particular problem.