Problem On Starting program

 Problem On Starting program

I am using following options to program LPC2132 micro-controller: -
1. Flash utility (ISP)
2. ZELTEX Parallel programmer through Superpro.

I am facing problem that randomly few of LPC2132 ICs (after programming & verification of Chksum) are not working but some of them does work.
My target hardware is same for both the cases. Once LPC2132 does not work on my target hardware then even though i am replacing it on to a working hardware, then also it does not work.

Kindly help me out.