See the note in Roles > Options > Realm > Post Type Usage > "problems with types / taxonomies?"

NOTE: If your custom Taxonomies or Post Types are not shown above, they are not being defined properly. Try a different taxonomy/post type plugin. If they are displayed but cannot be enabled/disabled, they may be defined too late in the WordPress initialization sequence. If you use your own registration calls, hook them to the init action with a priority of 1 or 2. Otherwise, force Role Scoper to initialize later (and possibly break compatibility with other plugins) by adding this to wp-config.php, ABOVE the "stop editing" line: