Jython run scripts problem (2.2.0a0 on Mac OSX 10.3.8)

[scott]

I installed darwinports and did a "sudo port install jython"

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scott$ which jython
/opt/local/bin/jython

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Jython works in interactive mode as shown below:

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pyprogs$ cd hotbits/
hotbits$ ls
flips50.py      jythoninstall.py randomX          randomflip.py
hotbits$ jython
Jython 2.2a0 on java1.4.2_05 (JIT: null)
 >>> # Truly random (radioactive decay triggered) coin flip
 >>> from randomX import randomHotBits
 >>> r = randomHotBits()
 >>> if r.nextByte() < 0:
...     print 'tails'
... else:
...     print 'heads'
...
tails

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Jython *doesn't* work if I save the above as a script and try to run it. 
It refuses to run the script and simply starts up in interactive mode:

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hotbits$ jython randomflip.py
Jython 2.2a0 on java1.4.2_05 (JIT: null)
 >>>

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Question:
How can I run scripts as expected (outside interactive mode)?

Thanks in advance.