Think from what I can gather, their debt has got to such a level that they can't even manage to make the interest repayments on it. So the plan is to pump money into it and reduce the debts they owe The Walt Disney Company by transferring it into equity, with payments to be made at a later date. In reducing the debt they should be able to manage it by paying of the interest on it year on year through their own revenue.
It's an odd one, TWDC have obviously got enough faith and belief that the park is a viable operation that will eventually run at a profit, but how they've let it get to such a state without acting sooner is questionable. As Gavin said, it's baffling at how bad things are given the number of visitors they get and the prices they charge.