How to fix this error when downloading OS X Mavericks from the Mac App Store?

Hello Apple Users,

Can anybody please help me cz I am having an error when downloading OS X Mavericks (10.9) for the Mac App Store.

The download is starting as normal with a high speed. Then when it gets to 2.21GB it stops downloading suddenly and reveal me the following message:

Then when I click "OK", the following come up:

And When I click on "FREE UPGRADE" nothing happens. So I am obliged to delet the app from the Launchpad and redownload it from the beginnig, to be

re-stuck on 2.21 GB 😟

Please help me cz I really want to pgrade my os x to mavericks.

Thanks in advance 🙂