How do you launch the site? If you mean using VS 2005 debugger then just keep clicking the continue button on errors. It will handle the errors then it will run the upgrade scripts that will add that missing stored proc that is raising an error, then you should see the setup page with a button to create initial site data.
If you are not using VS and used release files then type a space in web.config to recycle tha app. It should handle that error.
Hope it helps,
Joe