zy:

Common/Common.csproj

       <HintPath>dlls\NPOI.OpenXmlFormats.dll</HintPath>
     </Reference>
     <Reference Include="System" />
+    <Reference Include="System.Configuration" />
     <Reference Include="System.Core" />
     <Reference Include="System.Data.SQLite">
       <HintPath>dlls\System.Data.SQLite.dll</HintPath>