SIGSEGV runtime error in Shortest Path in Binary Trees

Could someone please tell me why this is giving me a runtime error (SIGSEGV).

The problem is http://www.codechef.com/APRIL14/problems/BINTREE/

Here is my code for this problem: http://www.codechef.com/viewsolution/3734804

Please don’t ask problems from the On-going contest.