What is form 6198

Form 6198 is a form that calculates how much your are "at risk" with your company. In other words, how much money you have invested in the business. 

It comes into play when you report a loss from a business venture that is more than what you have invested in the venture. For instance, you may have invested $10,000 in a partnership, but the partnership reports a loss for you of $15,000 on your K-1 schedule. Since you only have $10,000 invested in the business, you can only deduct that amount of your current year tax return, the balance gets carried forward to future years.

I suggest you go back over the sections in your program where you reported business income. It may be from schedule K-1 entries or a small business reported on schedule C. Pay attention to the questions regarding "at risk" and make sure you answered them correctly.