[U-Boot] Writing to Flash. ..Error

Hello,

I am working with coldfire 5485 processor. this board is showing a problem in uboot When I am saving changes to the flash I am getting these error

Writing to Flash... Flash buffer write error at address ff802000

Command Sequence Error.

Block locked.

Vpp Low Error.

Can't write to protected Flash sectors

Could any one help me out on this problem

regards, Balan