HTMLHELP

I am trying to implement HtmlHelp in an existing project. I call it and it comes up fine, but when I resize the window bigger vertically, the app crashes, when I do it horizontally its fine. I created a new project and tested there and everything works fine.

I have tried passing many things for the hwndCaller....NULL, the apps mainwnd, etc...nothing changes the outcome.

BOOL ShowHelp(LPCTSTR szTopic, BOOL bIsLocal, HWND curwnd)
{
TCHAR szDir[MAX_PATH] = "";
if (bIsLocal)
{
DWORD dw=GetModuleFileName(AfxGetInstanceHandle(),szDir,MAX_PATH);
TCHAR* pchEnd = _tcsrchr(szDir,'\\')+1;
ASSERT_POINTER(pchEnd, TCHAR);
*pchEnd = '\0';
//_tcscat(szDir,_T("Help"));
_tcscat(szDir,_T("Filename.chm"));
_tcscat(szDir,_T("::/"));
_tcscat(szDir,szTopic);
}

HWND wnd=HtmlHelp(AfxGetApp()->m_pMainWnd->GetSafeHwnd(),szDir,HH_DISPLAY_TOPIC,NULL);
if (wnd != NULL)
return TRUE;
else return FALSE;
}

Anyone else ever have this problem?

Thanks for any info.