EnvDTE.Project.get_Properties() ComException

Hello everyone, I have a problem about addin develop as follows:

Problem:

    My request:In my addin, I need add my own menu to website project , and the language should be C#/VB.

    Method:  I do this in QueryStaus function. If parameter [commandName] is my own menu, then get current select project is website, then get the project language. Like follows:

     Array prjs = (System.Array)_applicationObject.ActiveSolutionProjects;
     if (prjs.Length == 1 )
    {
       Project prj_selected = (Project)prjs.GetValue(0);
       if (project.Object is VSWebSite)

       {
            VSWebSite objWebSite = (VSWebSite)project.Object;
            Property webSiteLang = project.Properties.Item("CurrentWebsiteLanguage");
                   
             if (webSiteLang.Value.ToString().Equals("Visual C#") || webSiteLang.Value.ToString().Equals("Visual Basic"))
            .....   

        }

      }

This is work well except in VS2010/2012, there is error as follows:

       System.Runtime.InteropServices.COMException (0x80029C4A): タイプ ライブラリ/DLL の読み込みエラーです。 (HRESULT からの例外: 0x80029C4A (TYPE_E_CANTLOADLIBRARY))   場所 EnvDTE.Project.get_Properties()

NOTE:

    OS:Win7

    VS:there are VS2005/2008/2010/2012 installed

Any one can help me?