Any business structure you consider must separate your personal debts and assets from your business debts and assets and then operate so that there is absolutely no commingling of the two. You will, therefore, want to avoid a sole proprietorship and a partnership which make your personal assets vulnerable in any legal action filed against your business.
Here is a link to the Iowa State Bar Association with information on starting a business in Iowa and the types of business structures you can form:
I think he was concerned about the other way around (his personal creditors going after the business assets), but the advice is still valid. However, coming out of a personal bankruptcy, most of that sort of thing should be taken care of unless you start in piling up personal debt. Note, that if they think you're hiding personal assets in the business whether you use a corporation or another entity, they might rightfully argue that they should have access to them.