|I would try downloading the file again. If you can, I would even try downloading it to another computer and then transferring it across the network or via a USB thumb drive.|
If it still fails, contact ubisoft's support.
I've had issues with other game manufacturer's updates doing something similar and it was usually a bad update that they hadn't tested thoroughly enough before releasing.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.