i'm trying to turn on the server but this is what is sais:

2013-01-13 16:34:01 [INFO] Starting minecraft server version 1.4.7
2013-01-13 16:34:01 [INFO] Loading properties
2013-01-13 16:34:01 [INFO] Default game type: SURVIVAL
2013-01-13 16:34:01 [INFO] Generating keypair
2013-01-13 16:34:02 [INFO] Starting Minecraft server on 210.50.41.107:25565
2013-01-13 16:34:02 [WARNING] **** FAILED TO BIND TO PORT!
2013-01-13 16:34:02 [WARNING] The exception was: java.net.BindException: Cannot assign requested address
2013-01-13 16:34:02 [WARNING] Perhaps a server is already running on that port?


why does it do that?i need help!