plpython (triggers?) and dropped attributes

I have a table with a plpython trigger defined on it in 7.3.4. I've
dropped a column from that table, and now I cannot get a plpython trigger
to run at all on that table. I've dropped both the trigger and function
and recreated them from scratch (not using "create or replace"), and I
still get the following error when I set off the trigger:

ERROR:  plpython: Cache lookup for attribute
`........pg.dropped.5........' type `0' failed

The trigger procedure has a plpy.info call as the first statement, and I'm
not seeing that output, thus I believe it's a problem in plpython. I
suppose this is a bug in plpython's trigger handler building up the
TD['new'] and TD['old'] structures. I figured I'd toss this out and see if
somebody familiar with the plpython code can spot the problem faster than
if I start muddling through the code blindly.

Any thoughts?