PIC32 stuck after long time

I am using a PIC32MX795F512L which sends CAN messages to a WiFly module (RN-171) using UART.

I receive messages over WiFi but after a longer time (20-60 minutes), the PIC seems to be stuck and I have to reset it. Below is the code for the UART initialisation, the message queuing and message sending.

TCPSending() is called every 200ms in an interrupt routine and PutInTXBuffer() is called whenever a CAN message is received (and then the ID and data are passed to the PutInTXBuffer function).

void InitUART()
{
    UARTConfigure(UART1, UART_ENABLE_PINS_TX_RX_ONLY);
    UARTSetFifoMode(UART1, UART_INTERRUPT_ON_TX_NOT_FULL | UART_INTERRUPT_ON_RX_NOT_EMPTY);
    UARTSetLineControl(UART1, UART_DATA_SIZE_8_BITS | UART_PARITY_NONE | UART_STOP_BITS_1);
    UARTSetDataRate(UART1, GetPeripheralClock(), 57600);
    UARTEnable(UART1, UART_ENABLE_FLAGS(UART_PERIPHERAL | UART_RX | UART_TX));
}

void TCPSending()
{
    if(UARTTransmitterIsReady(UART1) && U1STAbits.UTXBF == 0)
    {
        int i;
        for (i = 0; i < TXelements; i++)
        {
                putcUART1(WiFiTXBuffer[i].id >> 8);
                putcUART1(WiFiTXBuffer[i].id);
                putcUART1(WiFiTXBuffer[i].data >> 56);
                putcUART1(WiFiTXBuffer[i].data >> 48);
                putcUART1(WiFiTXBuffer[i].data >> 40);
                putcUART1(WiFiTXBuffer[i].data >> 32);
                putcUART1(WiFiTXBuffer[i].data >> 24);
                putcUART1(WiFiTXBuffer[i].data >> 16);
                putcUART1(WiFiTXBuffer[i].data >> 8);
                putcUART1(WiFiTXBuffer[i].data);
        }
        free(WiFiTXBuffer);                 // Deallocate the buffers memory
        WiFiTXBuffer = NULL;                // Re-initialize the buffer
        TXelements = 0;                     // Keeps track of the number of elements used
        TXallocated = 0;                    // This is essentially how large the array is
    }
}

void PutInTXBuffer(WORD id, QWORD data)
{
    int MoreAllocation = 50;

    WiFiTXPacket packet;
    packet.id = id;
    packet.data = data;
    if(TXelements == TXallocated)                               // Are more refs required?
    {
        TXallocated += MoreAllocation;
        // Make the reallocation transactional by using a temporary variable first

        void* temp = realloc(WiFiTXBuffer, (TXallocated * sizeof(WiFiTXPacket))); 

        // If the reallocation fails:
        if (!temp)
        {
            TXallocated -= MoreAllocation;
        }

        WiFiTXBuffer = (WiFiTXPacket*)temp;


        free(temp);
        temp = NULL;

    }

    WiFiTXBuffer[TXelements] = packet;
    TXelements++;
}

I think the problem has to do with a memory leak but I can't seem to find it.