Problem in performance of calling a dialog in DLL(Windows programm

Hello guys!
I have a MFC program called Tester in which a function (Secondfunction) of
a dll is called;
I use VC++ 2008 and have two part in my project(First part: my dll project
named
 DlgInDLL which includes dll source (dll1.cpp) Second part: my Tester
MFC type project)

First, in Tester I push Secondfunction button and then the corresponding
function in dll, will be called;
Inside Secondfunction function, I call a dialog procedure named
SecondDlgProc;
I send a structure including a string buffer and its size, through final
argument of DialogBoxParam and in the procedure, parse this string into 3
substrings and add to a ComboBox control belonging to dlls dialog named
Select Reader and then select one of these substrings and send it to the
Secondfunction,&.

Once I push Secondfunction button in Tester, I see good result and
Select Reader is appeared and I select one the substrings and works fine!
But, when I press Secondfunction button again(In run time!), substrings
wont be added to ComboBox!!!

I put my code( Dialog procedure + Secondfunction) below,
I debug my program and in Second call of Secondfunction, I see the string
buffer is parsed correctly, but I dont know why wont substrings be added to
ComboBox in Second time?!!
Because the debugger doesnt give clear information in this case to me!!

I, myself, think the problem is from this line, but I dont know why:

SendMessage (hwndComboBox, CB_INSERTSTRING, p, (LPARAM) Reader1) ;

The codes:

BOOL CALLBACK SecondDlgProc(HWND hwndDlg,
                             UINT message,
                             WPARAM wParam,
                             LPARAM lParam)
{
    HWND hwndComboBox ;
    hwndComboBox = GetDlgItem(hwndDlg, IDC_COMBO1);
    TCHAR* Reader=new TCHAR[30];
    static TCHAR * pReaderName;
    int nPtr=0;
    //counter
    int n=0,i=0;
    int a=0,iIndex;
    static int iLength;
    static buff* pad=new buff ;

    switch (message)
    {
    case WM_INITDIALOG:
        pad = (buff *) lParam ;
        SendMessage (hwndComboBox, LB_RESETCONTENT, 0, 0) ;// clear contents of
the combobox;
            while(pad->m_ReaderBuff[nPtr] != '\0')
            {
            Reader[0] = '\0';
            while(pad->m_ReaderBuff[nPtr] != '\0')
            {
            Reader[nPtr-n]=pad->m_ReaderBuff[nPtr];
            nPtr++;
            i++;
            } // while do
            nPtr++;
            n=++nPtr;
            TCHAR* Reader1;
            Reader1=new TCHAR[i+1];
            for(int k=0;k<i;k++)
                Reader1[k]=Reader[k];
            Reader1[i]='\0';
            i=0;
            static int p=0;
            SendMessage (hwndComboBox, CB_INSERTSTRING, p, (LPARAM) Reader1) ;
            delete[]Reader1;
            p++;
        }// while do

    case WM_COMMAND:
        if (LOWORD (wParam) == IDC_COMBO1 && HIWORD (wParam) == LBN_SELCHANGE)
{

      // Get current selection.
      iIndex = SendMessage (hwndComboBox, CB_GETCURSEL, 0, 0) ;
      iLength = SendMessage (hwndComboBox, CB_GETLBTEXTLEN, iIndex, 0) + 1 ;
      pReaderName =new TCHAR[iLength];
      SendMessage (hwndComboBox, CB_GETLBTEXT, iIndex, (LPARAM) pReaderName)
;
}

         if(LOWORD (wParam) == IDOK)
{
             pad->m_ReaderBuff=new TCHAR[pad->size];
             pad->m_ReaderBuff[0]='\0';
             while(pReaderName[a]!='\0')
             {
              pad->m_ReaderBuff[a] = pReaderName[a] ;
              a++;
             }
              pad->m_ReaderBuff[a]='\0';
      pad->size=iLength;
      delete[] pReaderName;
      EndDialog (hwndDlg, TRUE) ;
      return TRUE ;
}

          if(LOWORD (wParam) == IDCANCEL)
{
              EndDialog (hwndDlg, FALSE) ;
              return TRUE ;
}
        break;
    }
    return FALSE;
}

EXPORT void WINAPI SecondFunction(){
    buff* param=new buff;
    param->size=46;
    param->m_ReaderBuff=L"ACS READER 0 \0 ACS READER 1 \0 ACS READER 2 \0 \0";
    TCHAR szBuffer[100];

    if(DialogBoxParam (g_hModule, MAKEINTRESOURCE(IDD_DIALOG2),
        NULL, SecondDlgProc, (LPARAM) param))
    {
    TCHAR* reader=new TCHAR[param->size];

    for(int i=0;i<param->size;i++)
    reader[i]=param->m_ReaderBuff[i];
    wsprintf (szBuffer, TEXT ("The value of reader is %s."), reader) ;
    MessageBox(NULL,szBuffer,L"Note",MB_OKCANCEL);

    delete[]reader;
    delete param;
    MessageBox(NULL,L"The Second Function Succeeded.",NULL,0);
    }
    else
    MessageBox(NULL,L"The Second Function Failed.",NULL,0);
}

I also have Uploaded my project in a host server and its link address is
here:(7.36 MB)
http://www.ziddu.com/download/5307424/DlgInDLL.rar.html

Could I ask you tell me what the problem is with this code?
Any help would be greatly appreciated,

I need so help, Please help me!!
Creative22