Python Portability--Not very portable?

[W. eWatson]

In my on-again-off-again experience with Python for 18 months, 
portability seems an issue.

As an example, my inexperienced Python partner 30 miles away has gotten 
out of step somehow. I think by installing a different version of numpy 
than I use. I gave him a program we both use months ago, and he had no 
trouble. (We both use IDLE on 2.5). I made a one character change to it 
and sent him the new py file. He can't execute it. I doubt he has 
changed anything in the intervening period.

A further example. Months ago I decided to see if I could compile a 
program to avoid such problems as above. I planned to satisfy that need, 
and see if I could distribute some simple programs to non-Python 
friends. I pretty well understand the idea,and got it working with a 
small program. It seemed like a lot of manual labor to do it.