I was told that the Treaty of Versailles was the start of ww2, both economical and political, why so?

The fact is, it really wasn't. From an economic standpoint, WWII happened when it did because the Nazis were forced by their own baleful economic policies, to begin their conquests ahead of time and plunder their neighbours to sustain the Reich (Adam Tooze's Wages of Destruction covers this, and economic aspects of WWII, superbly). From an economic and political perspective, the Nazis came to power because of the dislocation brought about by the Great Depression, which was itself unrelated to the Treaty of Versailles. The German economy had more than recovered from the Hyperinflation of the early 20s, and the country had enjoyed immense prosperity prior to 1930-31.

The fact of the matter is, the Treaty of Versailles was pretty much a dead letter even before Hitler came to power. The issue of reparations had been dealt with in 1929 with the Young Plan (which greatly reduced reparations), the Dawes Plan in 1924 (which stabilized the German economy and currency, and provided Germany access to foreign capital to pay reparations), and the Lausanne Conference in 1932, which postponed them indefinitely. The issue of Germany's western borders had been settled at Locarno in 1926, with Germany also joining the League of Nations, and Germany was due to receive full sovereignty over the Saarland and Rhineland by 1935-36. Aside from Germany's eastern borders and the disarmament (which was increasingly undermined thanks to German cooperation with the USSR from 1926 onwards), there really weren't that many issues left. Plus, Hitler and the Nazis' opposition to Versailles was shared by pretty much every party, great and small, in the Reichstag, so there was nothing special about them in that regard either.