$SqlCmdItem.CommandText = $("EXEC [zoomfs].[LandmarkParcelChecker]");
You defined the command type as StoredProcedure, so SqlCommand expects only the SP name, nothing else.
But you wrote a EXEC in front, so it looks mor like a SQL statement and then you have to define the parameter in the command text.
Remove the EXEC or add the parameter name like
$SqlCmdItem.CommandText = $("EXEC [zoomfs].[LandmarkParcelChecker] @PackageID");
See SqlCommand.CommandType Property => Remarks:
When you set the CommandType property to StoredProcedure, you should set the CommandText property to the name of the stored procedure.
