Why is this throwing an unhandled exception?

[robertpires]

this is the header file I am using and the function that is throwing errors, was providing by professor so it has to be right

template<class ItemType>
class Node
{
private:
	ItemType       item;
	Node<ItemType> *next;
public:
	Node();  //default constructor
	Node(const ItemType &anItem); //none default constructor #1
	Node(const ItemType &anItem, Node<ItemType> *nextPtr); //none default constructor #2
	void setItem(const ItemType &anItem);
	void setNext(Node<ItemType> *nextPtr);
	ItemType getItem() const;
	Node<ItemType> *getNext() const;
};

/*other functions*/ 

template<class ItemType>
Node<ItemType>* Node<ItemType>::getNext() const {
	return next;
}

The function that I am getting in trouble with is this one (I tested all prior functions which worked fine).

bool getNextUnvisitedCity(char citeh, char &adjCity){
	if(!(isInMap(citeh)))
		return false;
	else {
		for(int i=0; i<9; i++){
			if(flightMap[i].city_name==citeh){
				if(flightMap[i].adjacent_city=NULL)
					return false;

				Node<char>* tempPtr;
				tempPtr=flightMap[i].adjacent_city;

				while(tempPtr->getNext()!=NULL){
					if(!(isVisited(tempPtr->getItem()))){
						adjCity=tempPtr->getItem();
						return true;
					}
					else
						tempPtr=tempPtr->getNext();
				}

				if(flightMap[i].adjacent_city->getNext()!=NULL){
					if(!(isVisited(flightMap[i].adjacent_city->getItem()))) {
						adjCity=flightMap[i].adjacent_city->getItem();
						return true;
					} else
						return false;		
	} } } } } 

the error I'm getting is
Unhandled exception at 0x00fe4a76 in Assignment 12.exe: 0xC0000005: Access violation reading location 0x00000004.

and the specific error is

this | 0x00000000 {item=??? next=??? } | const Node<char> * const

I failed my test because of the SAME exact thing but I'm not doing anything incorrectly!

[cire]

If adjacent_city on line 11 can be nullptr, then lines 13, 22, 23 and 24 will result in dereferencing nullptr.