Why does this happen and how can I get around it??

Brand new workbook (no data)
Create a UserForm (UserForm1)
Add a Textbox and a command button.

The only code is in the TextBox AfterUpdate Event.

Private Sub TextBox1_AfterUpdate()
Unload Me
End Sub

Crashes with an "Automation Error"??

I'm trying to use this scenario in a different workbook and need
to close the present userform to open a second one but I can't
even get the above to work in a new blank workbook.

Any ideas??

Thanks,
John