A welfare state is reducing some people's economic security to add to other people's economic security. There is no way that can produce a net increase in entrepreneurship. Plus, a welfare state adds more regulations that block private enterprise in various areas and make it more difficult. Moreover, a welfare state hurts economic growth overall, also dragging down the total amount of entrepreneurship.
I'm going to throw this out there: If I had a proper social safety net and I didn't have to worry about things like health insurance, I'd be much more likely to start a business and take some risks.
So, uh... sources? Because the parent article had sources. Simply from a logical standpoint, it makes sense to me that having a safety net would make person less risk averse.