I have successfully built an open source application using py2app for 10.7 Lion. However, when users try to open the application on 10.6 Snow Leopard, they get the following error:
ImportError: dlopen(/Applications/Mnemosyne.app/Contents/Resources/lib/python2.7/lib-dynload/PyQt4/QTWebKit.so, 2): Symbol not found: _kMDItemDownloadedDate
Referenced from: /Applications/Mnemosyne.app/Contents/MacOS/../Frameworks/libQtWebKit.4.dylib
All of my dependencies are installed using MacPorts. How can I fix this to allow Snow Leopard users to open the application as well? This application is originally linux-based, so there should be no Lion-specific code.
I eventually solved this by installing Snow Leopard on a separate partition on my Mac and re-installing everything in Snow Leopard, then building the application there. The Snow Leopard-built application runs fine in Snow Leopard, Lion, and Mountain Lion.