Hey so also, check the permissions.
That's one of those things that I often forget to do when I see an error like that.
So do an
in the /bin/64/ directory
if you don't see an at all in the "drwxrwxrwx" permissions column, then it's not executable. You can chmod it:
Just do 755:
chmod 755 bitcoin
(make sure you're in that directory, or declare the full path)
Don't mean to be patronizing to the original poster - this is directed at all who google this - I just love this bitcoin idea, and I want to see more people use it, so if there are some linux newbs out there, I wouldn't want a simple permissions problem to stop them from trying it out.
Then as xlcus pointed out, you may still have to execute it as