Carbon applications made with Project Biulder doesn't run on mac os


I finally managed to compile my snake game with Project Builder, but it doesn't seem to run under mac os 9.2. The application is displayed as a document and doesn't have a creator code or file type. If I set the filetype to APPL it still refuses to run (error -39)

I thought a carbon application should be able to run on both OS 9 and OS X... Or did I do something worng with project builder?