The VISA selection box references a specific file that may not be on the target machine. Even if it is, the strings "com 1", "com 2", etc may not refer to the same port on the target computer. The following link address this issue: http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/db5e81eafc9a463886256aa8005ea2b1?OpenDocument
Also check to see that the same VISA run time engine is on both machines.
Jeremy Braden
National Instruments