Here are a few suggestions:
1. Make sure your visaconf.ini file gets used with your executable:
http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/75ba53ad6886719a8625660c0077f0df?OpenDocument
2. Make sure the machine that is running the EXE has the same version of VISA that your development machine has.
3. As a debuggin aid, I would suggest building an EXE that displays on the front panel the 'Error Out' cluster of VISA property nodes, etc. You may be encountering an error and may not be aware of it...