I really do hate giving these sort of 'non answers', but to try and be of help, I just need a little more info...

The message simply states one of the objects you are referencing (trying to use) in this method has not been created. Which line does the exception occure on? Beyond that, I would say that once you find out which line (which object: yes5, close4, uiapane3...etc) the exception is talking about, look further into the Desktop.UIA[] process from which your program is trying to gain a reference to find out why you are not getting one as you expect... without knowing what Desktop.UIA[] does, I don't have a good guess for you as to what it might be.

Perhaps somone else here who has seen what you're doing before can offer more of a solution for you, best of luck!