c++ - MAPIInitialize fails -

c++ - MAPIInitialize fails -

under windows 7(64bit) & outlook 2010(64bit), phone call mapiinitialize initialize mapi, there popup message saying:

"either there no default mail service client or current mail service client cannot fulfill messaging request.please run microsoft outlook , set default mail service client."

then mapiinitialize homecoming 0x80004005, indicating fail initialize mapi.

the same programme works under windows vista(32bit) & outlook 2007(32bit).

what problem? thanks.

c++