A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
For your future reference, there is an Office for Mac forum that will get you better answers: PowerPoint 2011 for Mac
I use a Wacom tablet myself and used to experience spurious page jumps, sometimes from ordinary hand gestures!
If you have a tablet Prefs panel (in System Preferences), please open it. With a Wacom, I clicked on the Grip Pen (their name for a stylus) and turned the Tip Double Click Distance field all the way down to off. That solved it for me.
Of course, your mileage will vary. Your may have a different make and certainly a different model, so your control panel is likely very different. But by playing with the options you can discover settings that will tame the stylus.