Can't enable any add-ons in OSX

I am running Blender 2.5 alpha 2 on Mac OSX.

But when I click any of the ‘enable add on’ buttons nothing is enabled (ie it does not appear when searching the tools/commands using the spacebar).

Is this a bug for the Mac version or am I doing something wrong?

I am trying to install the awesome fracture script.

For 2.5 alpha 2 on the mac for me it seems to work fine (enable Add Gears addon and I can search for gears). If you want more addons you need to have a much more recent version of blender than the ancient version you are using. Get from http://www.graphicall.org/builds/

Thanks Richard.
Updating to the latest stable build did the trick. Now I have to learn to use the new Fracture script…