Error: Flash Download failed - "Cortex-M4":Contents mismatch

Hi
I am trying to flash mk64fn1m0vll12 (http://www.keil.com/dd2/freescale/mk64fn1m0vll12) this is available as a board by name Freedom-K64F

When I try to flash the board using KEIL I get the following error

Spend a lot of time searching on web but no success. Can someone help me

Contents mismatch at: 0000001FH (Flash=00H Required=DFH) !
Verify Failed!
Error: Flash Download failed - "Cortex-M4"

More details:

Target info:
------------
Device: MK64FN1M0VLL12
VTarget = 3.300V
State of Pins:
TCK: 0, TDI: 0, TDO: 0, TMS: 0, TRES: 0, TRST: 1
Hardware-Breakpoints: 6
Software-Breakpoints: 8192
Watchpoints: 4
JTAG speed: 1429 kHz

Full Chip Erase Done.
Programming Done.
Contents mismatch at: 0000001CH (Flash=00H Required=C4H) !
Contents mismatch at: 0000001DH (Flash=00H Required=DCH) !
Contents mismatch at: 0000001EH (Flash=00H Required=FCH) !
Contents mismatch at: 0000001FH (Flash=00H Required=DFH) !
Verify Failed!
Error: Flash Download failed - "Cortex-M4"
Flash Load finished at 13:07:59