Well, I think the only way to move forward with this is to try to 
figure out what the actual error is.  Something is wrong in printing it 
out to stderr, and it would be helpful to understand why it is not 
being output.  Perhaps this is some buffering issue.  You could try to 
redirect stderr to a file, using something like this i the finally 
clause:
sys.stderr = open("/tmp/err.txt", "w", 0)