dialog on cancel run time error : Run-Time Check Failure #2 - Stack around the variable xxx was corrupted.

Hi I have mfc  mdi   application;

I have a dialog schedDlg   which  invoked from a parent window  TignSetup

like this     :   schedDlg evtDlg(0,1);  evtDlg.domodal();

the dialog shows up and everything is ok;

however when I click cancel button on the dialog i get run time error:Run-Time Check Failure #2 - Stack around the variable 'evtDlg' was corrupted.

my guessing is that    because schedDlg does not provide a desctructor   the oncancel  method fails

but as i see it  the constructor does not allocate any memory which is needed to be released

CScheduleEventDlg::CScheduleEventDlg(int rows, int enableServiceScroll, CWnd* pParent /*=NULL*/)
	: CDialog(CScheduleEventDlg::IDD, pParent)
{
//{{AFX_DATA_INIT(CScheduleEventDlg)
	m_currState = "";//NULL;//_T("");
	m_effFromDay = 0;
	m_effFromMonth = 0;
	m_effFromYear = 0;
	m_effToDay = 0;
	m_effToMonth = 0;
	m_effToYear = 0;
	m_excFromHour = 0;
	m_excToHour = 0;
	m_friday = FALSE;
	m_monday = FALSE;
	m_saturday = FALSE;
   m_sunday = FALSE;//
	m_thursday = FALSE;
	m_tuesday = FALSE;
	m_frequency = -1;
	m_wednesday = FALSE;
	m_intervalHour = 0;
	m_runTimeHour = 0;
	m_runTimeMin = 0;//
	m_suspend = FALSE;
	m_type = -1;
	m_excFromMin = 0;//
	m_excToMin = 0;
m_intervalMin = 0;
	//}}AFX_DATA_INIT
m_rows = rows;
  m_enableServiceScroll = enableServiceScroll;
  m_initFromGlobalSetup = 0;
}

I am skeptic about the first item m_currState="";    

Any suggestions how to fix the problem will be appreciated