Had been trying to get a very simple custom action using nbtstat.exe to work. Surprisingly I kept receiving an error message that the file could not be found.

I modified the custom action specifying the exact path to the nbtstat executable and verified that it was there, however the custom action still said that the file could not be found.

After some searching I found this article and it not only explained the issue very clearly but provided a fix for the problem. I hope this helps someone else.

http://scottiestech.info/2009/06/20/calling-a-32-bit-system-command-from-a-script-in-x64-windows/