Those look to me like Namecoin addresses. You need to use the namecoin(d) client and its RPC port.
They are TestCoin addresses. (BitCoins for developers)
If you're running testnet, you need to the RPC port with a 1. So, 18332.
I tryed with that but it gave an error.
So I opened the bitcoin.conf file and saw that I also had to change there. Now it's working fine.
But I have another problem now. How do I save on fees sending mass payments? Because with sendmany I have to pay 0.5BTC for 1000 transactions.