download linux problem

hi hippo:

I follow the uclinux-dist step to build the linux,then i get the zImage file.

So i download the nios_0.ptf file to the DE2,and run the command:

nios2-download -g zImage

but it can't work,these happen:

Using cable "USB-Blaster [USB-0]", device 1, instance 0x00

Downloading:0x00D00000 ...%

processor is already paused

Downloaded 1196KB in 16.8s (71.1KB/s)

Verified failed

Leaving target processor paused:

But i config the link address:0x00500000 in the linuxconfig.

And i did not enable the net.

I don't know why?