>>>

>>>do WhoHas with "\\servername\myfolder\myapp.exe" 
>>>

>>>
>>>I get message "No Open Files Found for '\\servername\myfolder\myapp.exe'.
>>>
>>>Is my syntax incorrect?
>>
>>It is correct.
>
>Could it be because what I refer to as a server is actually another computer on my peer-to-peer network (and not Server 2003)?

Only files open through a share are included. It cannot see files opened locally.
I didn't test it on peer-to-peer network.