Jerry,
What exactly are you trying to do with this Form? Are you accessing it from other parts of the calling Form? Is it supposed to be Modal?
The problem is that your private variable has been defined, it's not going out of scope and so it still exists, even though the Form itself has been disposed. Without knowing what you are trying to accomplish with the form, I can't tell you what's the best way to handle it, so give me some more information.
~~Bonnie