can not execute my app,help

I build a nios system,first with a cpu. on_chip_memory , ssram, timer ,uart and it work well, it print the hello world to my uart.

then I add a flash and a tri_state_bridge to the nios system,compile and download it to my board, and also in the nios IDE I new a Hello World program and run it as hardware ,then it happen as follow:

Using cable "ByteBlasterII [LPT1]", device 1, instance 0x00

Pausing target processor: not responding.

Resetting and trying again: FAILED

Leaving target processor paused

Why? can anyone help me ,I am new to it.

Thanks in advance.