Can't get my Puff Pastry shells to rise
The Pepperidge Farm site offers some tips for baking related to the rise:


Always preheat your oven for a minimum of 15-20 minutes before baking, because Puff Pastry depends on even heat to rise and puff. Place pastries 1 inch apart.
If you want a flaky thin and crispy pastry that's not very puffy, prick the unbaked Puff Pastry all over with a fork, which lets steam escape while baking.
To create a tart with an extra puffy crust: take a knife and score two lines around the edge, then prick the area inside this border with a fork.


I would begin by verifying that these tips were observed. Also, I would verify that your oven bakes consistently (i.e. no hot/cold spots). Preheating can be very helpful in resolving this. Also, you can put in a pizza stone or other heat regulating product, and monitor the temperature with a probe thermometer in water in different areas of the oven.