Posting the error from Excel will do little good. Even if it was a common error, with out your code or formula we will only be able to give a general answer. Post your code!
I will tell you this: The error message you have posted is given when you are using a property or method out side its designed context. Like using a graph plot property to modifiy a font. You may think that you can use what ever you are using, but Excel is telling you that it cannot use part of your code from that "line" or within a "With or If" block with the other parts of the code you are using.
Tell us what you are trying to do and show us the code! Hope this helps both of us. JSW