Orchestrator fails to import 64 bit powershell modules. Cmdlets do not work.

Orchestrator spawns processed in 32bit powershell. So if you use any activity that uses 64bit powershell modules. Those modules fail to load.
To overcome this encapsulate your script in the following lines.

C:\Windows\Sysnative\WindowsPowershell\v1.0\Powershell.exe -NonInteractive -Command {
###Enter your script here###

}


Reference:
http://www.purgar.net/using-exchange-2010-cmdlets-in-system-center-orchestrator/