I saw you followed the SaveDefinitions
suggestion from Henrik Schachner that you got in your other post. Good, that was also my suspicion.
But there is also another issue with the manipulate in slide 5. It is continually updating. You can stop that with the option TrackedSymbols
{t, -4, 8, Appearance -> "Open"}, SaveDefinitions -> True, TrackedSymbols :> {t}]