What do you mean by "references a declaration that the super class already contains"?

The .H file contains only constant declaration, like:
#DEFINE ONEKB 1024

If your code use the constant ONEKB as:

IF THIS.FileSize > ONEKB
ENDIF

Then, you need to include the .H file in your class.

>Do you mean adding new code to the subclass that needs a new declaration or adding new code that references a declaration that the super class already contains?