无法加载文件或程序集..系统.数据.实体.dll.

/"应用程序中的服务器错误。

无法加载文件或程序集"file:///C：''程序文件 （x86）''引用程序集''Microsoft''Framework.NETFramework''v4.0''System.Data.Entity.dll"或其依赖项之一。系统找不到指定的文件。

在我的 web.config 文件下面 - 可能有什么问题？如果我登录并使用该应用程序，一切正常。如果我离开应用程序并且下次尝试输入时超过 15 或 20 分钟不使用它，我收到上面的错误

感谢您在高级方面的任何帮助

<?xml version="1.0"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=169433
  -->
<configuration>
  <configSections>
    <!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
    <section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=4.4.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false"/>
  </configSections>
  <connectionStrings>
    <!--<add name="***" connectionString="Data Source=winserver;Initial Catalog=***;USER ID=***; Password=***; MultipleActiveResultSets=true;" providerName="System.Data.SqlClient"/>-->
    <add name="***" connectionString="Data Source=plcentral.ca;Initial Catalog=***;Integrated Security=False; User ID=***;Password=*** providerName="System.Data.SqlClient"/>
    <!--<add name="***" connectionString="Data Source=(local);Initial Catalog=***;Integrated Security=True;" providerName="System.Data.SqlClient"/>-->
    <!--<add name="***" connectionString="Data Source=.'SQLEXPRESS;AttachDbFilename=|DataDirectory|***.mdf;Integrated Security=True;User Instance=True"
providerName="System.Data.SqlClient" />-->
    <!--<add name="***" connectionString="Data Source=***;Initial Catalog=***;Integrated Security=False; User ID=***;Password=***" providerName="System.Data.SqlClient" />-->
  </connectionStrings>
  <appSettings>
    <add key="webpages:Version" value="2.0.0.0"/>
    <add key="webpages:Enabled" value="false"/>
    <add key="PreserveLoginUrl" value="true"/>
    <add key="ClientValidationEnabled" value="true"/>
    <add key="UnobtrusiveJavaScriptEnabled" value="true"/>
    <add key="GoogleAccount" value="email@email.com"/>
    <add key="GoogleAccountPwd" value="password"/>
    <!--<add key="GoogleAccount" value="email@email.com"/>
    <add key="GoogleAccountPwd" value="password"/>-->
  </appSettings>
  <system.web>
    <customErrors mode="Off"/>
    <globalization culture="en-US" uiCulture="en-US"/>
    <compilation targetFramework="4.0" >
      <assemblies>
        <add assembly="System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
      </assemblies>
    </compilation>
    <httpRuntime maxRequestLength="20000000"/>
    <authentication mode="Forms">
      <forms loginUrl="~/Account/Login" timeout="2880"/>
    </authentication>
    <pages>
      <namespaces>
        <add namespace="System.Web.Helpers"/>
        <add namespace="System.Web.Mvc"/>
        <add namespace="System.Web.Mvc.Ajax"/>
        <add namespace="System.Web.Mvc.Html"/>
        <add namespace="System.Web.Optimization"/>
        <add namespace="System.Web.Routing"/>
        <add namespace="System.Web.WebPages"/>
        <add namespace="MvcJqGrid"/>
      </namespaces>
    </pages>
  </system.web>
  <system.webServer>
    <validation validateIntegratedModeConfiguration="false"/>
    <modules runAllManagedModulesForAllRequests="true"/>
    <handlers>
      <remove name="ExtensionlessUrlHandler-ISAPI-4.0_32bit"/>
      <remove name="ExtensionlessUrlHandler-ISAPI-4.0_64bit"/>
      <remove name="ExtensionlessUrlHandler-Integrated-4.0"/>
      <add name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%'Microsoft.NET'Framework'v4.0.30319'aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0"/>
      <add name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%'Microsoft.NET'Framework64'v4.0.30319'aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0"/>
      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0"/>
    </handlers>
  </system.webServer>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35"/>
        <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35"/>
        <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35"/>
        <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System" publicKeyToken="b77a5c561934e089" culture="neutral"/>
        <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Xml" publicKeyToken="b77a5c561934e089" culture="neutral"/>
        <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Data" publicKeyToken="b77a5c561934e089" culture="neutral"/>
        <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Transactions" publicKeyToken="b77a5c561934e089" culture="neutral"/>
        <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Core" publicKeyToken="b77a5c561934e089" culture="neutral"/>
        <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0"/>
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
  <entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework"/>
  </entityFramework>
</configuration>