simple_socket_server fail on ep2c35

when I run the simple_socket_server on ep2c35 development board , the jtag port print as follow.I don't how to deal with it.

nios2-terminal: connected to hardware target using JTAG UART on cable

nios2-terminal: "USB-Blaster [USB-0]", device 1, instance 0

nios2-terminal: (Use the IDE stop button or Ctrl-C to terminate)

Simple Socket Server starting up

Your Ethernet MAC address is 01:02:03:04:05:06

[lwIP]: See STDERR for expanded diagnosis translation.

[lwIP]: [init_done_func] Fatal: lwip_devices_init failed, perhaps ethernet inter

face.

[lwIP]: ERRNO: :

[lwIP]: See STDERR (FAULT_LEVEL is SYSTEM).

[lwIP]: FAULT_LEVEL is SYSTEM.

[lwIP]: FATAL Error, Restart required.

[lwIP]: Locking scheduler - endless loop.