[ruby-core:23110] File.executable? always returns false on Windows machine

On my machine, File.executable? is always returning false. I have tried 1.8p27. I am running on a Windows Vista x86 machine. The file system is NTFS. I can't think of anything unusual about my machine.

What are the semantic supposed to be? Most of the people I have asked get a value of true for all of the statements below, even for the File.executable? on the ttf file.

puts File.exists?("C:/windows/fonts/wingding.ttf")
puts File.readable?("C:/windows/fonts/wingding.ttf")
puts File.executable?("C:/windows/fonts/wingding.ttf") # Prints false only for me

puts File.exists?("C:/windows/notepad.exe")
puts File.readable?("C:/windows/notepad.exe")
puts File.executable?("C:/windows/notepad.exe") # Prints false only for me

With the 1.9 binaries, File.executable? returns true only if the file extensions is something like .exe. Again, it always returns true for the people I have asked.

Thanks,
Shri