I ran the miner overnight. Here are the miner's stats as of this morning.

[2013-07-20 08:25:36] Pool: http://coinworld.us:8884/
[2013-07-20 08:25:36] SOLVED 16 BLOCKS!
[2013-07-20 08:25:36]  Share submissions: 34172
[2013-07-20 08:25:36]  Accepted shares: 21492
[2013-07-20 08:25:36]  Rejected shares: 12680
[2013-07-20 08:25:36]  Accepted difficulty shares: 202557
[2013-07-20 08:25:36]  Rejected difficulty shares: 120888
[2013-07-20 08:25:37]  Reject ratio: 37.1%
[2013-07-20 08:25:37]  Stale submissions discarded due to new blocks: 301
[2013-07-20 08:25:37]  Unable to get work from server occasions: 2
[2013-07-20 08:25:37]  Submitting work remotely delay occasions: 1

Even though the rejection rate is high, the results are good.