Where can I find a worldwide General Aviation incident/accident ocurrence reports database?
No such official worldwide consolidated general aviation accident database exists. Most countries have their own, many smaller countries have none. 

The closest you will find to a consolidated aircraft accident database is the one maintained at the Aviation Safety Network's web site. However, this database does not qualify as an answer because it only covers airliner, military transport category aircraft and corporate jet aircraft safety occurrences since 1919, and then again only if the aircraft had 12 seats or more. Most other sites advertising such databases also have similar exclusions.