boot linux kernel error

I like linux ,also like the embed system design technology.
so i brought a development board(FriendlyARM mini2440),i have compiled the linux Kernel many times.
also it all doesn't work.
when i compiled the linux Kernel(linux-2.6.29) to a zImage and downloaded to board.
at the same time the rootfs.img download to board.
when boot the kernel it show that "Root-NFS: No NFS server available, giving up." ,"VFS: Unable to mount root fs via NFS, trying floppy."
"VFS: Cannot open root device "mtdblock3" or unknown-block(2,0)"
how can i do to this problem?
At last thanks for you spent the time to read my questions.

You must have it configured to mount an nfs share for your root file system. I do that with my ARM development board. You have to be sure your host has exported the appropriate directory tree for that, and that permissions and such are appropriately configured.