David,

Please make sure the dialog is not inside the Loop Wizard.

For example (before the installation takes place).

[ User Interface ]
! Wizard dialog definition(s)
Define Wizard Dialog "#1" (Welcome)
Define Wizard Dialog "#2" (Select Install Folder)
Define Wizard Dialog "#3" (Ready to Install)
Define Wizard Dialog "#4" (Readme)

! The Wizard Loop displays the dialog screens that the user sees in the installation
Loop Wizard
Wizard Auto Break
End

Or after the installation process (you can also place it before the Finish dialog):

[ Final User Interface ]
! Final wizard dialog definition(s)
Define Wizard Dialog "#1" (Finish)
Define Wizard Dialog "#2" (Readme)

! The Wizard Loop displays the dialog screens that the user sees in the installation
Loop Wizard
Wizard Auto Break
End

Does this help?

Thanks,