Subdirectory Framework Issue

I have developed on application in framework 2.0 .And upload it in server. Lets sat www.site1.com

Now I have one another application (ex Site2) in Framework 4.0 .I want to live this site for testing .I dono want to purchanse new servre for that. I want to upload it as a sub-directory of Site2.

Like www.site1.com/Site2

Rightnow I have uploaded site2 under site1.

Now when I run above URL(Site2) I got following error.

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Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.

Parser Error Message: It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level. This error can be caused by a virtual directory not being configured as an application in IIS.

Line 16: <compilation debug="true" targetFramework="4.0" />
Line 17:
Line 18: <authentication mode="Forms">
Line 19: <forms loginUrl="~/Account/Login.aspx" timeout="2880" />
Line 20: </authentication>

ny one knows how to solve this error?