Have you gone through the Personalize Movie options?
The Sequence part of that section will be influenced by whether or not you select "Auto Edit".
Have you seen the Adobe document on creating an Instant Movie?
One way I avoided the "repeats" was to select AutoEdit, and, then in Sequence, Time/Date, not Theme Order.
If worse comes to worst, you could consider using the Break Apart Instant Movie command and pick apart the Instant Movie.
Please review and consider. If questions or need clarifications, please do not hesitate to ask.