I agree to a large extent that the Treaty of Versailles and other peace settlements that followed World War I, were the root causes of World War II. However, there was also other factor that caused World War II.
The treaty of Versailles was designed to humiliate the Germans as the leader was forced to sign this treaty. Germany had to accept the full blame for starting the war. As the Germans were seen to be responsible for this, they were made to pay for the loss and damage caused by the war. Despite of their economic problems, they were made to pay a huge sum of money. Not only that, Germany's army and navy were to be kept small so that they would not be able to fight another war.
The Germans could not understand why they were forced to accept the blame for the war. They believed that they were not in a wrong position as they did not start the war.
Adolf Hitler, a young politician, promised that he would reverse the terms of the treaty if he gained power. After he gained power and became the new leader, he abolished the treaty of Versailles. He built up armed forces and wanted to bring all the Germans together into a Greater Germany. As Britain and France were having economic problems, they did not really pay attention on what the Germany had done. So Hitler used this opportunity to invade some countries. World War II broke out when Hitler invaded Poland and Britain and France had declared war on Germany. If there was no the Treaty of Versailles, Hitler would not think of invading other countries and so World War II would not have started.
However, the treaty of Versailles was not the only cause of World War...