IMUCarmen and others, like afbcamaro stated, it's the permissions on the file. When you move the replacement file in there, you must modify the permissions on it to be 644, or RW-R--R--. You can use a terminal emulator or a file browser that can change permissions. Then reboot and you should be good to go. Any files to be replaced in the system areas need these permissions. If you guys aren't sure on getting stuff to work with these sorts of testing, don't worry about it. One of the other people can test it, and as TDM has shown, I'm sure he'll release a beta 3 with the fixes implemented in a very timely manner. I just hate to see one of you guys modify something you really didn't want to modify, then it's glorious fun to fix it.
Edit: If changing the permissions like this manually does not work, then the permission changer likely did not actually change the permissions. Possibly no actual root privileges on whatever app you used?