Why doesn’t the erase function work with Word 2010?

http://ift.tt/1iZHv9S

I recently bought Office 2010. I can get a stylus pen to work with it, but I can’t get the eraser function to work in Word (but it does work in Onenote). I have seen instruction videos where people use Office 2010 with the same pen and eraser, like this one (http://ift.tt/1jLmjQ3) so I know it should be possible. What am I doing wrong?

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