Mecanim how to stop animation from going sideways?

I clamped a run_impulse animation from an animations package I downloaded and made a run animation. But when I pressed play I realized that the run animation made the character progressively go sideways. It seems the original animation does the same thing.

Here is a video of it: http://www.youtube.com/watch?v=m62W2buA0zk&feature=youtu.be

And here is an image of the settings of the fbx file: http://i.imgur.com/lvjDCeL.png?1?6997

I tried adjusting the offset like it says in the tutorial video, but while it brings down some settings it highers the others which would cause it to not go straight again. I hope someone can help me with this. Thanks.