My understanding is that you have defined the Service Levels (or that default service levels are active) and you are trying to view a call for a user who doesn't have the rights (access rights) to view the Service Levels. You will need to give the user "view only" permissions for the Service Levels.
Hope this helps,
Modesty is good!! But remember, all your life other people will try and take your achievements away from you, don't make it easy for them.