I should add that the full version information is:

Python 2.5 (r25:51908, Aug 15 2007, 11:38:03) 
[GCC 4.0.1 (Apple Computer, Inc. build 5367)] on darwin

Also, in my actual code (a much larger file, in a project using ll.xist
and other libraries), the error manifests differently:  I get
"TypeError: 'int' object is not iterable" on startup the first time it
loads, then it appears to run subsequent times, but behaves bizarrely. 
Specifically, *none* of the branches of the if statement run (verified
by putting a nonsense symbol after the if statement, and at the
beginning and end of each branch of the if statement; the "no such
symbol" error concerns the one *after* the if statement).  On neither
run is the "non-keyword arg after keyword arg" reported.