Anyone know what this means and a step-by-step guide on how to fix it?

Line 14: 
Line 15:   <system.web>
Line 16:     <compilation debug="false" strict="false" explicit="true" targetFramework="4.0" />
Line 17: 
Line 18:     <authentication mode="Forms">

I'm fairly new to ASP.net.

Help will be greatly appreciated.
Thanks in advance

Hi,

Does this error occur in IIS or Visual Studio? If IIS, which version are you using? or are you opening a web site from IIS in Visual Studio? Please provide more details.

This will happen if you run the web application from IIS and the application pool is set to 2.0 but attribute of targetFramework is set to 4.0 in web.config. In this case, you need to change the application pool to Framework 4.0.

Provide details please. upgrading your fremework might help.

Your settings on IIS do not match what you have in the config file on line #16. Your web is probably running on 2.0. If you are, remote line #16 from your config, or go to IIS and change the application pool to run on 4.0.

commented: This is the most likely cause. +0