Sorry, that page cannot be editted

Do what? Ok I have a custom theme and the menu page and sidebar pages cannot be editted. I have chmodded both files to 777 to complete my editting so I know its not a permission thing, and I have contacted the author of theme as well as my host to track down the error. When I click on the update file from the dashboard it brings up a new page that simply says, “Sorry, that page cannot be edittied.”

Any suggestions you can provide that I have not already thought of would be great!

Thanks!