Configuration Error: Web.Config[No Relevant Source Line] Options

[asoundmind]

Hi there, I recieve this error

Server Error in '/integrate' Application.
--------------------------------------------------------------------------------
Configuration Error
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: An error occurred loading a configuration file: Access to the path 'C:\Inetpub\wwwroot\integrate\web.config' is denied.


Configuration Error : Web.Config [No Relevant Source Line] Options


Source Error:

[No relevant source lines]

Source File: C:\Inetpub\wwwroot\integrate\web.config Line: 0

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Version Information: Microsoft .NET Framework Version:2.0.50727.42; ASP.NET Version:2.0.50727.210

This is the scenario
1. The code was working fine before
2. I Copy the "integrate" folder, the folder where my code is, and made a backup "copy of integrate"
3. Then I copy the codes from development to production into the "integrate" folder
4. Run the code, I recieved the error
5. I revert back to original folder by DELETING all the files. Open the backup, copy all the files from "copy of integrate" to "integrate" folder.
6. Run the code, I recieved the same error
7. IIS Reset
8. Run the code, same error
This is the web.config

<?xml version="1.0"?>
<!-- 
Note: As an alternative to hand editing this file you can use the 
web admin tool to configure settings for your application. Use
the Website->Asp.Net Configuration option in Visual Studio.
A full list of settings and comments can be found in 
machine.config.comments usually located in 
\Windows\Microsoft.Net\Framework\v2.x\Config 
-->
<configuration>
<appSettings/>
<connectionStrings>
<add name="MSPConnString" connectionString="Data Source=JKTGRHXSAPPS2;Initial
 Catalog=ProjectServer;Integrated Security=True;"
providerName="System.Data.SqlClient" />
</connectionStrings>
<system.web>
<!-- 
Set compilation debug="true" to insert debugging 
symbols into the compiled page. Because this 
affects performance, set this value to true only 
during development.
-->
<compilation debug="true"/>
<!--
The <authentication> section enables configuration 
of the security authentication mode used by 
ASP.NET to identify an incoming user. 
-->
<authentication mode="Windows"/>
<!--
The <customErrors> section enables configuration 
of what to do if/when an unhandled error occurs 
during the execution of a request. Specifically, 
it enables developers to configure html error pages 
to be displayed in place of a error stack trace.
<customErrors mode="RemoteOnly" defaultRedirect="GenericErrorPage.htm">
<error statusCode="403" redirect="NoAccess.htm" />
<error statusCode="404" redirect="FileNotFound.htm" />
</customErrors>
-->
</system.web>
</configuration>

I am totally blur on what's going on here. If the webconfig and all the files are all the same with the original state, why is it giving that error?
Please do help. Thanks in advance.
//Jack