There's a delay with Cryptsy withdrawals just like it was yesterday (after which was resolved a huge payout was sent). These coins are already exchanged into BTC so we don't risk currency rate changing, but they're pending withdrawal. As far as I know, other pools are affected as well. It's Sunday so I'm not sure how fast it will be resolved, but I believe there's nothing to worry about.
Does this mean the pool is only using 1 exchange? I moved some rigs here from MC a few days ago and I like what you have done here but you should probably develop a few more trading options, especially if you expect the pool to continue growing. Besides helping to insulate from deposit /withdrawal issues, you will probably find the added book depth helpful.