Board Thread:Online Discussion/@comment-10993011-20150619012337/@comment-5424581-20150619034852

http://elderscrolls.wikia.com/wiki/Puncture

According to this page it has a range of 5 meters. Are you sure you're close enough? Also it's part of the "one-handed and shield" skill tree so I assume you have to be using a one-handed weapon and a shield.