Modeless dialog in IE through ATL/COM dll

Hello,

I am creating a ATL/COM component(dll) which adds the context menu in
IE. After clicking on that menu it calls annother ATL/COM componet
which shows the Modeless HTML dialog box.
The problem is everything opens fine but suppose when i right click
conext menu and that opens the other HTML Modeless dialog. as it is
Modeless I can also click on IE's any web page. When i click on any
link it open another instance of IE. And when I closes that 2nd
intance of IE i got exception of memory in my dll workspace.

[Unhandled exception at 0x777849cc in iexplore.exe: 0xC0000005: Access
violation reading location 0xeee9bee8.]

In Debug mode it shows the pointer here in dbgheap.c file's

extern "C" void * __cdecl _heap_alloc_dbg(size_t nSize,
        int nBlockUse,
        const char * szFileName,
        int nLine
        )
{
.................
}
 __finally {
            /* unlock the heap
             */
            _munlock(_HEAP_LOCK); <---- Here it shows
the problem
        }
        return retval;
}

--------------------------------------------------------------------------------------------------
And in Release mode:
void __cdecl __addlocaleref( pthreadlocinfo ptloci)
{
.....

InterlockedIncrement(&(ptloci->lc_time_curr->refcount)); <----
Here it shows the problem
}

-----------------------------------------------------------------------------------------------------
This is My Code snippet of creating HTML modeless dialog

CMMBDHTMLDlg *dlg = new CMMBDHTMLDlg();

    dlg->m_strType.Empty();
    dlg->m_strType=L"2"; //img case
    dlg->m_strSelItem=CString(strlink);
    QueryInterface(IID_IMMBUICOMP,(void**) &dlg->pComp);
    dlg->m_strUser=CString(p_bstrUserID);

    dlg->Create(MAKEINTRESOURCE(IDD_MMBDHTMLDLG));
    dlg->ShowWindow(SW_NORMAL);

I am deleting dlg here in CMMBDHTMLDlg class's

void CMMBDHTMLDlg::PostNcDestroy()
{

    CDHtmlDialog::PostNcDestroy();

        delete this;
}

Please tell me the issue.....

Klic