[Role] Admin : Comment Problem

If I set the ‘Edit Posts’ to group the users can see and moderate the comments. If I don’t set this role, user can not write new post into blog. The group is Contributor – Level 1. I try to create a user ‘Subscriber’ – level 0 but the problem is the same.

At the moment I edit code with a “more-role-check” in the:
edit-comment.php
comment.php
moderation.php
but I don’t like this solution

Someone can help me to resolve this problem? ??