链接异常的解决办法

求一个链接错误的解决方法
错误如下：
Linking...
RTCEvents.obj : error LNK2005: _CLSID_RTCClient already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _LIBID_RTCCORELib already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _DIID_IRTCDispatchEventNotification already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCEventNotification already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCWatcher already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCBuddy already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCPresenceContact already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCEnumWatchers already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCEnumBuddies already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCEnumProfiles already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCEnumParticipants already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCCollection already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCWatcherEvent already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCBuddyEvent already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCMessagingEvent already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCIntensityEvent already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCMediaEvent already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCParticipantStateChangeEvent already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCSessionOperationCompleteEvent already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCSessionStateChangeEvent already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCRegistrationStateChangeEvent already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCClientEvent already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCProfileEvent already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCParticipant already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCSession already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCProfile already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCClientProvisioning already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCClientPresence already defined in FarSessionDlg.obj
RTCEvents.obj : error LNK2005: _IID_IRTCClient already defined in FarSessionDlg.obj
Debug/FarSession.exe : fatal error LNK1169: one or more multiply defined symbols found
错误的意思是重复定义，可是我也没有定义这些，这些都是REFIID的一些值，系统提供的。
求高手指点，不胜感激。

[解决办法]