Mistakes are a major part of learning. If your learners have never made a mistake, then chances are that your content is not challenging enough. There is nothing wrong with learners making mistakes. In fact, learning through mistakes is an effective learning method.
eLearning courses are the best environment to allow your employees to make mistakes. They can make all the wrong decisions without the organization having to face the consequences. They can experiment and practice. If they fail, they learn from their mistakes and avoid repeating the same ones in real life.