I just voted the combination WP 3.3.1 and Cas auth plugin 2.4 to be broken.
I tried the fix proposed by pho3nixf1re (i.e remove the md5() call
in file cas-authentication.php, line 101. However, this does not work for me. Once, authentificated at the CAS server, i am just redirected to the wp-login.php page with an pre-filled username and password that is rejected.
@pho3nixf1re : is it the only thing you changed?