New mesh options missing?

This problem is probably going to have an obvious answer, but I’ll ask anyway for the sake of my sanity. When I add a mesh (such as a circle) and look in my tool shelf, the typical new mesh options aren’t visible. I’m not sure if I’ve done something wrong or messed with an option I shouldn’t have. I’m using Blender 2.56. Any ideas? Thanks.

The operator panel is only visible after you have added the object. If you have minimised this panel by accident you will have a very small + sign in the bottom right of the 3d view. press it to reshow this panel.
See here
If you don’t have this you’ll have to show screenshot/video/blend file. Anything at all rather than just it doesn’t work.
As an alternative F6 also show the same info when you add an object.

I apologize for my ignorance. I didn’t think for a moment that an icon on the right side of the 3D view could affect my tool shelf. Thanks for your time.