Zakir Naik has wrongly understood the Bhagavad Purana. He is wrongly portryaing Prophet Mohammad as the Kalki Avatar where as the truth is that Kalki Avatar will appear after millions of years (from 2013). Zakir Naik is just manipulating the facts to fit them to Prophet Mohammad and wrongly quoting Bhagavad Purana.

Sant Rampal Ji Maharaj has explained in detail in the following video.