Get-ADuser : Identity info provided in the extended attribute: 'Manager' could not be resolved.

Hi 

I'm trying to run the following command as part of my script to retrive all users that have a specified manager as their manager. 

Get-ADuser -Filter {(manager -eq "CN=Roman Podlisk,OU=YAM,OU=PTV,DC=IL,DC=Teva,DC=Corp")} -Server $Domain -Properties manager, displayname, mail, userPrincipalName 

For some reason when ever the command is run on a domain in the forest that isn't my user\computer domain i get the following error.

Get-ADuser : Identity info provided in the extended attribute: 'Manager' could not be resolved. Reason: 'Cannot find an object with identity: 'CN=My Manager,OU=YAM,DC=SomeThing,DC=Corp' under: 'DC=VE,DC=SomeThing,DC=Corp'.'.

At Z:\PS1_Scripts\First Multiple Function.ps1:19 char:9

+         Get-ADuser -Filter $Filter -Server $Domain -Properties manager, displayn ...

Thanks in advance for any help,

Oren Zipori