Web.config

<?xml version="1.0" encoding="utf-8"?>

<configuration>
  <system.web>
    <compilation debug="true" targetFramework="4.0"><assemblies><add assembly="System.Configuration, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" /></assemblies></compilation>    
  </system.web>
  <system.data>
    <DbProviderFactories>
      <remove invariant="System.Data.SqlServerCe.4.0" />
      <add invariant="System.Data.SqlServerCe.4.0" name="Microsoft® SQL Server® Compact 4.0" description=".NET Framework Data Provider for Microsoft SQL Server Compact" type="System.Data.SqlServerCe.SqlCeProviderFactory, System.Data.SqlServerCe, Version=4.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" />
    </DbProviderFactories>
  </system.data>
</configuration>