Kovid,
calibre 4.56 will not even launch one my MacBook Air under OS X 10.5.2. I, literally, just downloaded the file (5:20 5-19-2008)
attempting to run
Produced:
william-cooks-macbook-air:~ BillC$ lrf-meta
Fatal Python error: Interpreter not initialized (version mismatch?)
Abort trap
william-cooks-macbook-air:~ BillC$
typing
Produces
Python 2.5.1 (r251:54863, Feb 4 2008, 21:48:13)
[GCC 4.0.1 (Apple Inc. build 5465)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>