I’m also using cforms 9.3 with WP 2.7 and have found a possible incompatibility. When I click on “Update Settings” to save changes to a form, I receive a 406 error “An appropriate representation of the requested resource /prod/wordpress/wp-admin/admin.php could not be found on this server.”
This is my first cforms install, so it is also possible that I have messed something up.
*Edit to fix WP version number typo.