Problem: Can dhcp callout dll insert new row into

I current working on this dll, but i found the dll doesn't response to any of the cdatabase execute response? I have try all the cdatabase and sql in c++ console and found that it can be run. The database is open success and the sql statement is correct.

After then i put it into the dhcp callout dll, and compile success.

When i add it into the registry and try the dhcp server, it doesn't have any response database table. And i using sql server for the dsn.

Here is my code

#include "stdafx.h"
#include "callout.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

CDatabase dbCallout;

struct tm *newtime;
char am_pm[] = "AM";
__time64_t long_time;

CString strCmd, strPrimaryKey, strTime;
int nRetCode = 0;

BOOL APIENTRY DllMain( HANDLE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved )
{
switch (ul_reason_for_call)
{
case DLL_PROCESS_ATTACH:
break;
case DLL_THREAD_ATTACH:
break;
case DLL_THREAD_DETACH:
break;
case DLL_PROCESS_DETACH:
break;
} return TRUE;
}

DWORD CALLBACK DhcpControlHook(DWORD dwControlCode,LPVOID lpReserved)
{
switch (dwControlCode)
{
case DHCP_CONTROL_START: {
_time64( &long_time ); /* Get time as long integer. */
newtime = _localtime64(&long_time); /* Convert to local time. */

if( newtime->tm_hour > 12 ) /* Set up extension. */
strcpy( am_pm, "PM" );
if( newtime->tm_hour > 12 ) /* Convert from 24-hour */
newtime->tm_hour -= 12; /* to 12-hour clock. */
if( newtime->tm_hour == 0 ) /*Set hour to 12 if midnight. */
newtime->tm_hour = 12;

strPrimaryKey.Format("C%.2d%.2d%.2d%.2d%.2d%.2d", newtime->tm_year - 100, newtime->tm_mon, newtime->tm_mday, newtime->tm_hour, newtime->tm_min, newtime->tm_sec);
strTime = asctime(newtime);

strCmd = "INSERT INTO Callout_Control (control_id, control_desc, control_date) VALUES ('" + strPrimaryKey + "', 'DHCP server have started!', '" + strTime + "')";

dbCallout.ExecuteSQL(strCmd);
dbCallout.Close();

break;
}
case DHCP_CONTROL_STOP:
{

break;
}
case DHCP_CONTROL_PAUSE:
{

break;
}
case DHCP_CONTROL_CONTINUE:
{
break;
}
}
return ERROR_SUCCESS;
}

DWORD CALLBACK DhcpServerCalloutEntry(LPWSTR ChainDlls,DWORD CalloutVersion,LPDHCP_CALLOUT_TABLE CalloutTbl)
{

CalloutTbl->DhcpAddressDelHook=DhcpAddressDelHook;
CalloutTbl->DhcpControlHook=DhcpControlHook;
CalloutTbl->DhcpDeleteClientHook=DhcpDeleteClientHook;
CalloutTbl->DhcpPktDropHook=DhcpPktDropHook;
CalloutTbl->DhcpAddressDelHook=DhcpAddressDelHook;
CalloutTbl->DhcpNewPktHook=DhcpNewPktHook;
CalloutTbl->DhcpPktSendHook=DhcpPktSendHook;

dbCallout.Open(_T("CALLOUT"), FALSE, FALSE, _T("ODBC;"));

return ERROR_SUCCESS;
}

What wrong in this code? Can dll file insert new row into dsn? Some expert please help me!!!