issue Solved.
I kept a Break point at Exception class. Below are steps followed .
First External break point at BP_HEAD component .
In debug mode menu path BREAKPOINTS->BREAKPOINT AT-> BREAKPOINT AT EXCEPTION.
and provided exception class CX_SY_REF_IS_INITIAL.
this break point stops at exact point where it is taking difference of Development server and Quality Server. Some Custom fields are not available in quality and which are not required . we removed unwanted fields and now it is working 
Regards
Kalyan