We had the same experience. I took my DS (4 1/2) and the actual movie was fine. The short before hand had him flip over, shriek and bury his face into the chair. I find pg is a very broad category and some stuff is fine, others completely inappropriate.
Once he had calmed down, I did find that short useful to explain a little about religion and how people see gods etc. but yeah- it was too full on and should have had a warning.