Check under the Moderators & Forums > Forum Permissions
- Find which ever forum you can't do the stuff in and then make sure the "[Edit] Administrators" is not red.
- If it is then click on the "[Edit]" link
- On the new page select the radio box which says " Use Usergroup Default Permissions (Note: this will delete any previous custom permissions set)".
- Scroll to the bottom and hit Save.
Hopefully that will fix your problem.
N.B. The Administrator Permissions is the for the AdminCP only, ensure that you have not inadvertently given extra permissions to other administrators.