A friend of mine has Vista (64bit) installed and he was unable to open a PE64 exe I sent him. Any ideas as to why?

Possibly the dialogue resource? Or does Vista 64 just have no backward compat for Win XP64?

Both files are PE64 GUI 4.0 one of the two EXEs has an accompanying PE64 DLL file.

If anyone else has Vista 64 and wouldn't mind the files are on the projects and ideas portion of the board.

Really, the problem in dialogue resources can. Or can they somehow not are correctly compiled? How much I heard, PE64 should work under Vista correctly. Feryno the 64-bit debugger is developed, and on a branch http://board.flatassembler.net/topic.php?t=5045&postdays=0&postorder=asc&start=20 he wrote, that on Vista x64 RC2 all worked. I personally didn't check it, but you can ask at Feryno.

I don't think it's a compilation error because I've also sent him the PE64Demo in the fasm examples and it failed to work as well.

Maybe my friend's settings are configured in an odd way.