[chirp_users] New user with Mac issue: app won't start

[Grant Cunningham]

I've searched the Wiki and site, and can't find an answer to this problem. 

Downloaded the Mac version and the required Python runtime. Installed Python, rebooted, then tried to run the app.

Nothing happens; the app doesn't open, doesn't give an error message, icon doesn't appear in the dock, etc. Tried it on 2 very different machines: a MacBook Air running the latest version of Mountain Lion, and an old iBook G4 running Leopard (10.5.2) Problem is identical on both machines. It's obviously me, but what?

My search of the mailing list did turn up an issue from 04/2012 (apparently since fixed) that detailed similar behavior, and the workaround was to run the app from a folder which did not have a space; mine are both installed in the standard Applications folder, so that shouldn't be the cause.

I'm not at all familiar with Python; is there something I need to do besides simply installing it? Will it run on a G4, or does it require an Intel?