In September(?) 1997 Abbey Road Interactive were responsible for producing the first commercially available DVD in the UK, "Queen�s Greatest Flix", followed by the first feature film "The Graduate".
I cannot readily find the answer for the "World's first" commercial DVD but it could have been produced up to 12 months earlier based on the availability of commercial DVD players in Japan from November 1996...
http://museum.toshiba.co.jp/history/1goki/1998 dvd.html