I'm no expert, but I think in theory it goes something like this -
When they last refinanced, the only way RBS would do the deal was if they converted this £144m to equity. Basically that meant that, rather than loaning the money to LFC, that money was treated as cash introduced by the owners which theoretically increased the value of LFC by £144m. i.e. if we had zero in the bank and the owners put £144m in, the bank account then increased to £144m, and at that precise moment in time the club was worth £144m more than it was before the money was received.
By doing this, it meant that to get that money back, rather than LFC repay a loan, the owners would need to get that from any sale - i.e. in theory, having increased the value of the club by £144m, they would expect any subsequent sale to provide £144m on top of what we might have been worth before they introduced the cash.
All well and good, but they were then reliant on the market price being sufficient to cover the outstanding debt + their £144m + any additional profit they'd like to make. The price agreed with NESV (approx £300m) only covers (approx) the outstanding debt - there's nothing left over to give them their £144m and any profit.
Happy days - and with a bit of luck, they've borrowed that £144m from elsewhere and won't be able to pay it back, with all the nasty consequences that entails for the cancerous bastards!