_ApplicationPtr pOutlook("Outlook.Application") crash at Outlook20

hi,
   i try to get the Outlook version via MAPI call as follow:

   try{
       _ApplicationPtr pOutlook("Outlook.Application");  // crash
       LPCSTR pVersion = pOutlook->GetVersion();
   }
    catch (_com_error &e) {
    }

    Outlook 2003 can use the code without any problem. But it crashes my 
Outlook 2007. May I know why it is happen? May I get Outlook version via
any 
others method?

Regards,
Siok Peng