Power Pro - Briggs and Stratton - Automatic Starter Issues?

Very similar to the earlier question that Barnie left, I too have a Briggs and Stranton PowerPro lawn tractor, which will not start. Yesterday, I cut my lawn and mulched the leaves. Today, it just won't start. At first I thought it was the battery, so I gave it a jump. Now (like Barnie's mower) all the starter does is whine - and really bad! I told my wife today that I think the starter gear is stripped, but I'm not a mechanic, and I don't know for sure. I found a bit of intrigue with Barney's note, but am faced with the same delimma.

Any ideas?