Porting 32-bit to 64-bit C program "Exception Thrown: Read Access Violation 0xC0000005"

I am using VS2017 and have the following lines of C code (sorry can't post all contents of function):

char        *dptr;                  /* Global variables */
static u_int16_t vers;  
...
static int32_t 
read_row(database_t *dbase, table_t *table, int32_t col_flag, int32_t flag) {

    row_t       *rowptr;
    char        marker;
    void        *new_row;
    table_t     *t_new;
    size_t      row_length;
    size_t      row_ =  1;

    marker = *dptr++;

    if (vers < VERS && marker != ROW) {
        return -1;
    }   

    /* Create a new row */
    t_new = table;
    row_length = t_new->row_length;
    new_row = calloc(row_, row_length);
    rowptr = new_row;
    if (rowptr == NULL)
    return -1;
    ... 

The last line is causing "Exception thrown at 0x00000000778745A0 (ntdll.dll) in ****.exe: 0xC0000005: Access violation reading location 0x00000000787745A0" error.

During debug, when I hover my pointer on calloc, I can see its value is "0x000000013f63dc94". But somehow, the exception is thrown and this value is never assigned to new_row (its value remains "0xcccccccccccccccc").

I have noticed that this exception is thrown when calloc has a value >"0x00000001********". It seems to work fine if 8 MSB of the address are 0. The definition of calloc() is from corecrt.malloc.h:

_Check_return_ _Ret_maybenull_ _Post_writable_byte_size_(_Count * _Size)
_ACRTIMP _CRT_JIT_INTRINSIC _CRTALLOCATOR _CRTRESTRICT
void* __cdecl calloc(
    _In_ _CRT_GUARDOVERFLOW size_t _Count,
    _In_ _CRT_GUARDOVERFLOW size_t _Size
    );

Any ideas about what could be causing this exception and how to fix it would be appreciated. Btw, I am using Win 7 Pro with 8GB RAM.