2009/4/4 Sander Sweers <sander.sweers at gmail.com>: Bah, of course you need to open the files writable :-( This > outfile = open('/tmp/myoutfile') > errfile = open('/tmp/myerrfile') Should be outfile = open('/tmp/myoutfile', 'w') errfile =open('/tmp/myerrfile', 'w') Greets Sander