Ошибка при использовании пространства имен

1>------ Build started: Project: Gui, Configuration: Debug Win32 ------
1>Build started 18.03.2015 23:44:08.
1>InitializeBuildStatus:
1> Touching "Debug\Gui.unsuccessfulbuild".
1>GenerateTargetFrameworkMonikerAttribut e:
1>Skipping target "GenerateTargetFrameworkMonikerAttribute " because all output files are up-to-date with respect to the input files.
1>ClCompile:
1> All outputs are up-to-date.
1> Gui.cpp
1>Gui.cpp(14): error C2872: 'Application' : ambiguous symbol
1> could be 'c:\program files (x86)\reference assemblies\microsoft\framework\.netframe work\v4.0\system.windows.forms.dll : System::Windows::Forms::Application'
1> or 'e:\vs2010\visual studio tools for office\pia\office12\microsoft.office.int erop.excel.dll : Microsoft::Office::Interop::Excel::Appli cation'
1>Gui.cpp(15): error C2872: 'Application' : ambiguous symbol
1> could be 'c:\program files (x86)\reference assemblies\microsoft\framework\.netframe work\v4.0\system.windows.forms.dll : System::Windows::Forms::Application'
1> or 'e:\vs2010\visual studio tools for office\pia\office12\microsoft.office.int erop.excel.dll : Microsoft::Office::Interop::Excel::Appli cation'
1>Gui.cpp(18): error C2872: 'Application' : ambiguous symbol
1> could be 'c:\program files (x86)\reference assemblies\microsoft\framework\.netframe work\v4.0\system.windows.forms.dll : System::Windows::Forms::Application'
1> or 'e:\vs2010\visual studio tools for office\pia\office12\microsoft.office.int erop.excel.dll : Microsoft::Office::Interop::Excel::Appli cation'
1>
1>Build FAILED.
1>
1>Time Elapsed 00:00:00.23