Are you SURE you got version 1.31? If I am not mistaken, version 1.31 is protocol 67.

You may have gotten version 1.30.

When you start up Quake 3, bring up your console by pressing the "~" key. You should see on the right side "Quake 3 1.31" if you do have 1.31.

If it is, then I would either

1) Uninstall Quake 3 and then reinstall

or

2) Download 1.31 again.