Krups blender blade stops

I have a Krups Power Xtreme VI blender that refuses to blend. While making a daquiri one night my sister noticed a burnt rubber smell so she unplugged the blender and took the jar off. The small grey rubber gear that turns the blade had stripped itself almost completely groove free. I went online and found a replacement gear and a replacement blade. I thought it couldn't hurt while I had it apart right?
As soon as the parts came in the mail I went online and got directions on how to replace the gear and the blade. After I put the blender back together I plugged it in and saw that everything was spinning as it should be. Later that night I had to try it out so I threw mix and ice in to make a drink and the blad stopped spinning. It would spin for a second then stop. I emptied the jar and turned it back on and the blade spun just fine. The gear is not stripped at all and I hear the motor running just fine. But everytime I put anything in the jar the blades stop spinning. I wonder if there is something else wrong that caused the gear to get stripped in the first place. Any ideas at all I would really appreciate. I'm dying for a drink!!