Creating a company culture that supports helping each other and identifying ways of improving allows new people to rapidly learn from their mistakes. It also allows new personnel to have face time with different departments and different individuals as well as involvement in the processes and workflows of different co-workers. Culture is everything. It allows questions to lead directly to solutions.
I believe that company culture is far more powerful than employee training. While manuals and interactive training can be helpful, nothing will replace experienced employees assisting new ones. Companies ought to focus more on folding new employees into company culture and allowing experience and knowledge to naturally flow from co-worker to co-worker. Interdepartmental communication is paramount.