Unfortunately you sound as if you may be in an situation where you owe more on the home than the current market value. The first thing you should do is call your lender and talk about your situation with them. They may have some options for you to restructure your loan and equity line of credit to be more manageable.
If they are unable to do that for you and you must sell your home then you need to have both lenders send you their short sale packets which will outline all of the documentation they will require for you to sell your home. You can not sell the home without the lender who is holding the equity loan to agree to the sale. That amount is due when you sell the property as the property is security for the loan.
Start with your lender and if you need more assistance you can feel free to contact me directly.