Thanks Tanget !! I have tried changing my %count = (); to my %count; and loop part i didnot understand. I thought $device is somthing which we are looking in both the arrays or it's just any x value ?

DEBUG( "DEBUG Difference:\n");
DEBUG( "DEBUG: - $_\n for @difference" );
DEBUG( "DEBUG: - Intersect:\n ");
DEBUG( "DEBUG: - $_\n for @intersect )";
DEBUG( "DEBUG: - Union:\n ");
DEBUG( "DEBUG: - $_\n for @union " );
[download]

I am still getting the same error ...