Mtgox has been having problems with LR withdrawals for over a month now. Here's their latest notice about it.
[UPDATE] July 18 -- 1:30AM GMThttps://mtgox.zendesk.com/entries/20239036-important-notice-libertyreserve-delays
Please be advised that we are still seeing shortages in the availability of LibertyReserve Dollars. We put in orders last week but they have yet to arrive. Once we have received them we will begin processing withdrawals immediately.
The LibertyReserve shortages appear to be ongoing, so we strongly suggest that you avoid withdrawing via LibertyReserve if you need quick access to your funds.