I found a bug on WordPress 2.7 version. I am not sure where to report the bugs. If this is wrong place, please move it to appropriate location.
if we use "chr(0)" without quotes we are getting the posts are not updated.
a. Disable the visual editor when writing
b. Click on add new to create new post (http://www.mydomain.com/wp-admin/post-new.php)
c. put some random title and use chr(0) in post input box
d. click publish
I tried on couple of my 2.7 blogs and am getting the error.