Problem in programming flash

Hi,

I had written code to program shadow flash from internal RAM. While
testing shadow flash might be the RCW got corrupted and now i am not
able to flash my MPC anymore.

Currently i am not even able to program the flash. However program
running out of RAM is possible.

 I am not able to view the shadow flash and normal flash. The FLEN bit
remains set always which actually should have allowed to access flash.

Can anyone please suggest me how can i clear my shadow flash now and 
program it.

Regards
Veeresh