Script works but trying to understand error generated

Hi all,

Wrote script to parse sub OU's of a specific parent OU.  Then for each of the sub OU's parsed, enumerate any computers within those OU's.  When I run my script, it generates two errors but then proceeds to run the script/output successfully.  Just wondering if anyone knows why the error kicks out?  Curious why PS doesn't like it.

$objOUS=Get-ADOrganizationalUnit -filter * -Searchbase "ou=Workstations,ou=West,dc=contoso,dc=com" | sort | foreach {$_.Name}
ForEach ($objOU in $objOUS)
{
Get-ADObject -filter * -searchbase "ou=$objOU,ou=Workstations,ou=West,dc=contoso,dc=com" | sort | foreach {$_.Name}
}

The following error is generated twice then proceeds to process the script successfully:

 Get-ADObject : Directory object not found
At C:\temp\oumem.ps1:4 char:1
+ Get-ADObject -filter * -searchbase
"ou=$objOU,ou=Workstations,ou=West ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~
    + CategoryInfo          : ObjectNotFound: (:) [Get-ADObject], ADIdentityNo
   tFoundException
    + FullyQualifiedErrorId : Directory object not found,Microsoft.ActiveDirec
   tory.Management.Commands.GetADObject

Thanks