The NI-Spy utility installs automatically with NI-VXI 2.0 and higher. It is available only for 32-bit operating systems. This utility is a powerful way to catch all calls to the NI-VISA DLL, NI-VXI DLL, and NI-488.2 DLL.
Try this link to get the latest version.
http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/b2aaef28cd4207ba86256b0300485414?OpenDocument
Richard