c++ mysql sqlstring crashes 0xC0000005 unable to read memory

usr = getstr((char*)"User: ", -1, 128);
pw = new char[128];
pw = getstr((char *)"Password: ", '\0', 128);

I don't know what getstr does, but casting a string literal to a char* is an immediate sign that you're going to do something very, very, wrong. Use a std::string and the c_str() member function instead. I'm also looking at your plethora of deletes and feeling the potential for bad news right there - you should use a scoped pointer to control the memory, as you're begging for leaks.

Building on Steve Townsend's answer perhaps your loop is your issue.

The following is a good loop example because next() gets called immediately moving the internal cursor to the first item and populating it.

res = stmt->executeQuery("SELECT * FROM `estglob`");
while (res->next()) 
{
    cout << "id = " << res->getString(1);
}

In your code you are calling first() without then calling next() internally I believe the first() function moves the cursor to before the start and the first call to next() moves the internal cursor to the first item.

The new code is here:

Driver *driver;
Connection *con;
Statement *stmt;
ResultSet *res;
string fld;
char *fldName = "divisa";

int i;
char *url, *database, *usr, *pw;

url = (char *) calloc(256, sizeof(char));
database = (char *) calloc(64, sizeof(char));
usr = (char *) calloc(64, sizeof(char));
pw = (char *) calloc(64, sizeof(char));

url = DBHOST;
database = DATABASE;
usr = getstr("User: ", -1, 64); // Get user home made function
pw = getstr("Password: ", '\0', 64); // Get password home made function
cout << endl;

try {
    driver = get_driver_instance();
    con = driver->connect(url, usr, pw); // create a database connection using the Driver
    for (i=0; i<64; i++) pw[i] = '\0';

    con->setAutoCommit(0); // turn off the autocommit
    con->setSchema(database); // select appropriate database schema
    stmt = con->createStatement(); // create a statement object

    res = stmt->executeQuery("SELECT * FROM `estglob`");

    while(res->next()) {    
        fld.assign(res->getString(fldName));
        cout << fld;
    }

    _getch();
    cout << endl << "Cleaning up the resources .." << endl;

    // Clean up
    con -> close();
    free(res);
    free(driver);
    free(con);
    free(stmt);
}
catch (SQLException &e) {
    cout << endl << "ERROR: SQLException in " << __FILE__;
    cout << " (" << __FUNCTION__<< ") on line " << __LINE__ << endl;
    cout << "ERROR: " << e.what();
    cout << " (MySQL error code: " << e.getErrorCode() << ")";
    //cout << ", SQLState: " << e.getSQLState() << ")" << endl;

    if (e.getErrorCode() == 1047)
    {
        //
        // Error: 1047 SQLSTATE: 08S01 (ER_UNKNOWN_COM_ERROR)
        // Message: Unknown command

        cout << "\nYour server does not seem to support Prepared Statements at all. ";
        cout << "Perhaps MYSQL < 4.1?" << endl;
    }

    _getch();
    return(EXIT_FAILURE);
}
catch (std::runtime_error &e)
{
    cout << "ERROR: runtime_error in " << __FILE__;
    cout << " (" << __FUNCTION__ << ") on line " << __LINE__ << endl;
    cout << "ERROR: " << e.what() << endl;

    _getch();
    return(EXIT_FAILURE);
}

return(EXIT_SUCCESS);

And here the callstack at error point:

msvcr90d.dll!memcpy(unsigned char * dst=0x002bf794, unsigned char * src=0x00445355, unsigned long count=0x0000000f) Línea 314 Asm

msvcr90d.dll!memcpy_s(void * dst=0x002bf794, unsigned int sizeInBytes=0x0000000f, const void * src=0x00445355, unsigned int count=0x0000000f) Línea 67 + 0x11 bytes C

msvcp90d.dll!std::char_traits::_Copy_s(char * _First1=0x002bf794, unsigned int _Size_in_bytes=0x0000000f, const char * _First2=0x00445355, unsigned int _Count=0x0000000f) Línea 582 + 0x16 bytes C++

msvcp90d.dll!std::_Traits_helper::copy_s >(char * _First1=0x002bf794, unsigned int _Size=0x0000000f, const char * _First2=0x00445355, unsigned int _Count=0x0000000f, std::_Secure_char_traits_tag __formal={...}) Línea 714 + 0x15 bytes C++

msvcp90d.dll!std::_Traits_helper::copy_s >(char * _First1=0x002bf794, unsigned int _Size=0x0000000f, const char * _First2=0x00445355, unsigned int _Count=0x0000000f) Línea 706 + 0x22 bytes C++

msvcp90d.dll!std::basic_string,std::allocator >::assign(const std::basic_string,std::allocator > & _Right= erróneo, unsigned int _Roff=0x00000000, unsigned int _Count=0xffffffff) Línea 1067 + 0x25 bytes C++

msvcp90d.dll!std::basic_string,std::allocator >::assign(const std::basic_string,std::allocator > & _Right= erróneo) Línea 1052 C++

testMySQL.exe!wmain(int argc=0x00000001, wchar_t * * argv=0x008d4a30) Línea 65 + 0x8d bytes C++ testMySQL.exe!__tmainCRTStartup() Línea 579 + 0x19 bytes C testMySQL.exe!wmainCRTStartup() Línea 399 C kernel32.dll!77391194()

[Los marcos siguientes pueden no ser correctos o faltar, no se han cargado símbolos para kernel32.dll]
ntdll.dll!77c7b495()
ntdll.dll!77c7b468()

Change fld.assign(res->getString(fldName)); to fld = res->getString(fldName);

You are not alone,
this is a recent problem in Teeworlds ddrace mod too. And as I googled I saw many others have the same problem (just google for: getString mysql windows).
It basically happens when getString accesses a value of a column with varchar's longer than 15 chars and if you use a different compiler for your app than they used for compiling the mysql cpp connector also you need to choose the right (/same) compiler settings (/MD, /MDd, /MT, /MTd). There are f.e. mysql cpp 1.0.5 connectors build with VC90.CRT and others build with VC80.CRT. You can read about this stuff here...
Why do I need to know?
CAUTION: binary compatibility on Windows

Found this information at:
http://bugs.mysql.com/bug.php?id=56742