Someone posted how to fix it here: http://flickr.com/groups/flickrhacks/discuss/72157594224232713/72157605715983607/.

Seems to be broken at the moment. :(

gasoline's fix to the script seems to have stopped working.

Doesn't appear to be working any more :(

Glad I could help.

This script stopped working! :(

It gives you:
Poke failed! [2,1]

And the javascript console says:
http://userscripts.org/scripts/show/5200/Facebook Autopoke 2.0: Auto-Poke failed -- Error Code 2.1: The confirmation page was retreived and the post_form_id was found (909e87aa89ba581840f78e1c86fd6ba1" /><input /><input /><input />divdiv