Font substitution error when using Flash 5

I have just upgraded my Macromedia Flash from 5 to 8, and I keep getting errors with the fonts! When I open my projects from Flash 5, I get this error message that calls for a font substitution. If I revise a project from Flash 8, it says that my fonts are wrong! I have reformatted my computer already and reinstalled Flash 8, but the fonts are still unavailable! Can anyone help? Thank you!
