The configuration for what apisnap considers the default PI Server is found in the pilogin.ini file. Which is in the %pihome%\dat\ folder.
You should something like:
Is the name listed, the name of you PI Server?
Many thanks Jerome and Kelsey,
I find that the servername configured in pilogin.ini file is PISVR1 but the correct PI server name is PISRV1.