Over in the general problems forum, Alaa Elkholy has posted a problem with the crossword activity from the games module in 2.0:
http://moodle.org/mod/forum/discuss.php?d=168126
For what is worth, I am getting the same error. Mac OS 10.5 Firefox 3.6.13 and Safari 5.0.3. I am using a glossary to populate the crossword. Other games from the module seem to be working fine.
Thanks.
Owen