I'm getting exactly the same error on Snow Leopard on a basic 'Hello World' example as shown below. It's a default installation of the AIR download. The path is properly set etc etc
MacPro:hello-world-html david$ adl helloworld-app.xml
Fri Nov 27 18:56:18 MacPro.local adl <Error>: The function `CGContextSetFontRenderingMode' is obsolete and will be removed in an upcoming update. Unfortunately, this application, or a library it uses, is using this obsolete function, and is thereby contributing to an overall degradation of system performance. Please use `CGContextSetFontRenderingStyle' instead.
Unimpressed with AIR as a development environment to since the Dreamweaver AIR plugin also barfs on java claiming the version is too old! I don't know if Adobe is actively trying to make AIR an unattractive option for RIAs.
I'm getting the very same error. When I installed Creative Studio 4 (which includes AIR) it says that AIR was installed, though I don't believe it is since it won't run AIR applications. Downloading the AIR installer directly results in the error message you described.
Hope someone has an answer for this.