vectors of structures

[axr0284]

Hi,
I have been trying to get this to work for sometime now but without success. I am trying to use a vector of structures in the following class:

class aodv_rit {

public:

/*This structure forms an RREQ PACKET.
	 * RREQ|SRC|DST|BID|SEQNO|TTL|FROM|TO
	 * 1   |1  |1  |4  |4    |1  |1   |1  bytes
	 */
	struct RREQ_STRUCT {
		unsigned char rreq_code; /* The destination ID*/
		unsigned char source; /* The source ID*/
		unsigned char destination; /* The destination ID*/
		int broadcast_ID; /*The ID of the broadcasted RREQ. This uniquely identifies each RREQ*/
		int sequenceNumber; /*The latest sequence number for this source*/
		unsigned char TTL; /*The Time To Live*/
		unsigned char FROM; /* which node sent it*/
		unsigned char TO; /* To which node was it sent*/
	};

std::vector<RREQ_STRUCT> rreq_in_Buffer; /*This is a buffer used by the callback function to store all incoming rreqs*/
}

The vector is then used in a function as follows:

int aodv_rit::recvPacket(unsigned char * packet, int size)
{
	int returnValue = 0;

RREQ_STRUCT rreq_object; /*The structure defining an rreq*/

/*Create the RREQ structure object*/
				rreq_object.rreq_code = RREQ;
				rreq_object.source = packet[1];
				rreq_object.destination =  packet[2];
				
				rreq_object.broadcast_ID = 0;
				for(int i=0; i<sizeof(int);i++) {
					
					rreq_object.broadcast_ID |= (unsigned char) packet[i+3];
					
					if(i != sizeof(int)-1) {
						rreq_object.broadcast_ID <<= 8;
					}
				}

				rreq_object.sequenceNumber = 0;
				for(int i=0; i<sizeof(int);i++) {
						
					rreq_object.sequenceNumber |= (unsigned char) packet[i+3+sizeof(int)];
					
					if(i != sizeof(int)-1) {
						rreq_object.sequenceNumber <<= 8;
					}
				}

				rreq_object.TTL = packet[3+2*sizeof(int)];
				rreq_object.FROM = packet[3+2*sizeof(int)+1];
				rreq_object.TO = packet[3+2*sizeof(int)+2];

				/*Store in rreq_in_Buffer*/
				rreq_in_Buffer.push_back(rreq_object); <<<<<<<<<<<<<<<<<

...
...
...

return returnValue;
}

The problem is everytime it reaches the <<<<<<<<< push_back function, I get an exception error. I traced it to inside the vector class:

void push_back(const _Ty& _Val)
		{	// insert element at end
		if (size() < capacity())
...
...
...

size_type size() const
		{	// return length of sequence
		return (_Myfirst == 0 ? 0 : _Mylast - _Myfirst);
		}

It seems _Myfirst does not exists. I get an address violation exception on the return line for size(). I am at a lost why that would happen. Did I not initialize the vector properly? Thanks for any help.
Amish