Sean's answer about status entitlement is still the best one, but you appear to have some other configuration issues.
Let's clarify the situation.
>>The state closed doesn't appear in the >>form for a service call or a WO, so >>nobody can close a SC. Either: a) you need to scroll down to see the status "Closed"; or b) you have status entitlement enabled and configured, such that you cannot see it (you may have to set the status to "Resolved" first); or c) the code value "Closed" has been deleted (or was not created yet).
>>What I need is that after a sc is closed, >>nobody can modify it, by they can close >>the sc. It is hard to second guess what you mean here in the second part of your remark. Status entitlement is really the way to go. Your requirement is the raison d'Ãªtre for status entitlement.
>>(Whe I set (access the folder entitlement)>>to true, I cannot acess to it in the role >>configuration console) Have you created folders?