Xcode 4.0.2 not launching after install

I installed the Xcode Snow Leopard beta in my Developer folder, but I decided to re-intall Xcode 4.0.2. So I deleted the Developer folder, and ran the installer.

Now 开发者_如何学Cwhen I try to open Xcode it just bounces a few times in the Dock, but doesn't launch.

Do I need to delete some other files to get it working?

Go to terminal and run this:

$ sudo /Developer/Library/uninstall-devtools --mode=all

After that finishes running, delete the /Developer directory again and reboot your computer (you must reboot your computer). When it comes back, re-install Xcode and you should be fine.