unhandled exception/linked list

[suraya]

hi guys, i am trying to implement a function insert in a hash table
i have this class and am trying to create a linked list
the code compiles however it doesn't run
can you please find whats wrong with my code?
while debugging i always get an unhandled exception in the while loop. can you tell me what does that mean?
thank you a lot

this is part of the code

  
class node {
public:
	typedef node <Key, Value> * ptr;
private:
	Key KEY;
	Value VALUE;
	node <Key, Value> * next;
public:
	node * NODE;
	node * head;
	node * tail;
	node (){
	
		KEY=0;
		VALUE=0;
	}
	node (Key & k, Value & v){
		
		KEY=k;
		VALUE=v;
	};
	Key & key(){
	
		return KEY;
	};
	Value & value(){
	
		return VALUE;
	};
	bool hashNext() const{
	
		return next!=NULL;
	}
	ptr getNext() const {
	
		return next;
	}
	ptr insert(Key & k, Value & v){
	
		if (NODE==NULL){

			NODE = new node;
			NODE->KEY=k;
			NODE->VALUE=v;
			NODE->next=NULL;
			tail=NODE;
			head=NODE;
		}
		else {
		
			NODE = new node;
			tail=head;
			while (tail->next!=NULL){
			
				tail=tail->next;
			}

			NODE->KEY=k;
			NODE->VALUE=v;
			NODE->next=tail;
			NODE=NODE->next;

		}

		return NODE;
	};
};

[ne555]

http://www.cplusplus.com/forum/general/112111/

[suraya]

thank you