Compiler Error Message: CS0433: The type '_Default' exists in both path abc and prq

My application works fine whenever i run under VS 2010. When I upload it on a server andi run from IIS it gives Complie error : CS0433:
'c:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\~\App_Web_dzybh5am.DLL' and 'c:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\~\App_Web_znctdhjf.DLL'

Error:

Line 146:    
 Line 147:    [System.Runtime.CompilerServices.CompilerGlobalScopeAttribute()]
 Line 148:    public class default_aspx : global::_Default, System.Web.SessionState.IRequiresSessionState, System.Web.IHttpHandler {
 Line 149:        
 Line 150:        private static bool @__initialized;
 

A quick search on google revealed that deleting those temporary files solved the problem. Is it useful to delete those temporary files, will it affect my application in future ?

I just want to know should I delete all files from temporary folder.

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