Go to your Steam folder and copy the 'steam.dll' file, now go to the Jade Empire folder and paste it in there.

Next rename the JadeEmpireLauncher to 'JadeEmpireLauncherBackup', then rename the JadeEmpire to 'JadeEmpireLauncher'. That will cause Steam to bypass the Launcher completely and just run the Game so no more Launcher crashes.

That's it! I hope you enjoy the game!