How can we solve keil 3 to keil 5 migration process

I have migrated the keil 3 code to keil 5 

when I build and fuse the Hex in keil 3 version it works fine and not in keil 5.

Sometimes i get output in keil 5 and sometimes not.

The appliation is oon graphical display & controller is LPC2378

Thanks in advance,

Manoj