We had a similar problem but it was after we had designed transferred in roles. Even though privileges were ticked we were getting errors. Removing them and reapplying them sorted it, don't think we needed an IIS reset after.
I've just given that a try but sadly am still expereincing the same issue
have you checked the permissions on groups or roles?
Your wrote something about groups but as far as i know, you should use the priviledges only on roles. Check the role "Analyst" if the rights for "Unresolve" are given.
Many thanks Christian. You're right, I hadn't checked the role. On further investigation Analysts did have right to open/update re-opened calls, but not un-resolved calls.
They do now :-)