Why does the program stop here?

void CWnd::GetWindowText(Cstring& rString) const
{
XXX ASSERT(::IsWindow(m_hWnd));



}

void Hyrut::OnOK()
{
// TODO: Add extra validation here
//UpdateData (TRUE);
CTestSet Set;
int hittad = 0;
CString strText;
XXX m_editBox.GetWindowText(strText);

Set.m_strFilter = CString("KundId = ") + m_strKundId;
Set.Open(CTestSet::snapshot, "Kund");
Set.MoveFirst();

while (!Set.IsEOF() && hittad == 0)
{
if(Set.m_Kund_KundId == strText)
{
Kunden Kund;
Kund.DoModal();
hittad = 1;
}

Set.MoveNext();

if (hittad == 0)
{

MessageBox ("Kunden fanns ej");
Registrera Regi;
Regi.DoModal();
}

CDialog::OnOK();
}

}