So the summary of the above:

UBS (Very very big bank) sell assets that they thought was worth $22 Billion for $15 Billion, but at the same time have to 'lend' the purchaser $11.25 Billion for them to buy the assets...

They lose $7 Billion on the deal and risk a further $11.25 Billion in the process.

HBOS are attempting to 'pull off' a similar deal by the way...