Hi!
I am not Guru, but I will try to give you some advice. Try to understand: help is not possible without seeing your program!!! What kind of controller you have been using? Program and data memories are inside or outside of chip? What is your program location at the rom memory? Give us more information if you really need help!
Maybe:
1. You have not declared the stack
2. You have putted program into interrupt table's memory space
3. You are using PUSH without POP
........... ? What's yet?