Hmm, Does every 64 bit machine has both folders side by side? Sorry I have never used 64 bit computer :( but hope to do it in coming months :D.
Hmm I dont know how to distinguish between to paths upon detecting is it running on 64 bit or 32 bit machine but I think you should get fine results using:
SpecialFolder.ProgramFiles on both computersbecause every computer with Windows OS, does have a Program File Folder
Best Regards,
Rizwan