Notice in WP 3.0.1 that get_option seems to sometimes return an Array, which was tripping up your unserialize call. Replace line 148 in extra_user_details.php with these two lines:
if ( get_option( 'eud_fields' ) ) $all_fields = get_option( 'eud_fields' );
if ( !is_Array( $all_fields ) ) $all_fields = unserialize( $all_fields );
That seems to fix it.
