I have been trying to get Natty to play Quake Live with no luck.
Installing in Chrome doesn't work at all -- it seems to download the XPI (firefox plugin file)
Installing in Firefox (latest -- at the moment this is 4.0.1) doesn't work due to incompatibility with v4.0.1.
Installing in older Firefox (v3.6.17) works, but I am still unable to play. Whenever quakelive.com is loaded, the browser is redirected to the install page (even when I have the plugin installed). This is the closest I have come to actually getting it working. Although, I'm not sure if this is a dead end. Many of the people on the Quake Live forums seem to use this solution.
Any help is appreciated.