Seems this is just a small naming bug in the ec_management.class.php file of the plugin. The quick fix is to search that file for line 306..
<select name="EC_accessLevel" id="accessLevel">
and change it to
<select name="accessLevel" id="accessLevel">
.. and make sure you have the latest version of the plugin. It seems this feature has only just been fully added. Incidentally you want to end up with
s:11:"accessLevel";s:7:"level_7";}
or similar in your database. ‘level_7’ gives editors access.
Hope that helps.
