here's what i did with that same problem

Settings "more" tab application manager scroll right to "all" select download manager force stop and then clear data and cache. reboot.

hope that helpes!

Here's what I did with that same problem.

1. Settings
2. More tab
3. Application manager
4. Scroll right to all
5. Select download manager
6. Force stop, and then clear data and cache
7. Reboot