Deploying ASP.NET application on IIS 7; got compilerVersion issue - asp.net

Question

I am trying to deploy two ASP.NET Application onto IIS 7. The first application I copied and pasted under wwwRooT folder and set Application Pool as Asp.NET 4.0 Integrated. For the second one, I created one virtual directory and set the Application Pool the same as the first application.
The first one works well, but the second one got exception:
The value for the 'compilerVersion' attribute in the provider options
must be 'v4.0' or later if you are compiling for version 4.0 or later of the .NET
Framework. To compile this Web application for version 3.5 or earlier of the .NET
Framework, remove the 'targetFramework' attribute from the element of
the Web.config file.

Answer 1

I had a similar problem and had to tell ASP.NET in configuration to use the 3.5 compiler as follows by modifying Web.config.
I've copied and pasted the following from my code. You have to change value="v3.5" to value="v4.0". The compiler type strings might also change.
<configuration>
<!-- ... other configuraiton stuff ... -->
<system.codedom>
<compilers>
<compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CSharp.CSharpCodeProvider,System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" warningLevel="4">
<providerOption name="CompilerVersion" value="v3.5"/>
<providerOption name="WarnAsError" value="false"/>
</compiler>
<compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" type="Microsoft.VisualBasic.VBCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" warningLevel="4">
<providerOption name="CompilerVersion" value="v3.5"/>
<providerOption name="OptionInfer" value="true"/>
<providerOption name="WarnAsError" value="false"/>
</compiler>
</compilers>
</system.codedom>
</configuration>
In my case the 2.0 compiler was being used instead of 3.5. I was working in an IIS 7, ASP.NET Website project.
You might glean additional insight from:
http://msdn.microsoft.com/en-us/library/system.codedom.aspx
http://msdn.microsoft.com/en-us/library/a15ebt6c%28VS.80%29.aspx