As I mentioned, you may have to dimension the variables  as Global, or Public as:

Global A as Variant
Global HF as Variant

or

Public A as Variant
Public HF as Variant

I believe either one will work.

I think the problem is that regular DIMensioned variables are only available in
the Modules, or UserForms
where they are declared.
If I remember right, Global variables are available to all
modules/classes/UserForms in the Application.
Public variables are available to other MS Office Applications.

(I may have those reversed)

Nevertheless, that should solve the problem.