Yes, the same problem appears to happen under Vista as well as prior versions of Windows. The method described here should work but you have to do a bit more work as there is presently no .REG file download FILExt has created. When sufficient numbers of people have tested this there will be a more formal writeup with a download.
If the Vista EXE association is damaged the location in the registry most likely changed is in this key...
[HKEY_CURRENT_USER\Software\Microsoft\Windows\Curre ntVersion\Explorer\FileExts\.exe]S
The "OpenWithList" and "UserChoice" subkeys probably have some program listed as opening the .EXE file extension. These need to be cleared and, when cleared, the system will go back to the default and the EXE extension should then work again.
You can do this by creating a .REG file with these lines in it...
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Windows\Curre ntVersion\Explorer\FileExts\.exe]S
[HKEY_CURRENT_USER\Software\Microsoft\Windows\Curre ntVersion\Explorer\FileExts\.exe\OpenWithList]S
[HKEY_CURRENT_USER\Software\Microsoft\Windows\Curre ntVersion\Explorer\FileExts\.exe\OpenWithProgids]S
"exefile"=hex(0):
Use cut/paste to copy these five lines to an editor like Notepad and then save the file with a .REG file extension. Copy the file to the misbehaving Vista machine and double click on it (or right click and select Merge). You will likely have to say OK to a number of different things (the user access control and the registry editor for certain) but afterward (and a restart to be certain) the system EXE association should come back