asp.net configuration error
<h2>Server Error in '/WebSite1' Application.</h2>

<p>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. </p>

<p>Parser Error Message: Could not load file or assembly 'System.Data.DataSetExtensions, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The system cannot find the file specified.</p>

<p>Source Error: </p>

<p>Line 35:       
Line 36:       
Line 37:       
Line 38:       
Line 39:      </p>

<p>Source File: F:\aspnet\WebSite1\web.config    Line: 37 </p>

<p>Assembly Load Trace: The following information can be helpful to determine why the assembly 'System.Data.DataSetExtensions, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' could not be loaded.</p>

<p>=== Pre-bind state information ===
LOG: User = suren-PC\suren
LOG: DisplayName = System.Data.DataSetExtensions, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
 (Fully-specified)
LOG: Appbase = file:///F:/aspnet/WebSite1/
LOG: Initial PrivatePath = F:\aspnet\WebSite1\bin</p>

<h1>Calling assembly : (Unknown).</h1>

<p>LOG: This bind starts in default load context.
LOG: Using application configuration file: F:\aspnet\WebSite1\web.config
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v2.0.50727\config\machine.config.
LOG: Post-policy reference: System.Data.DataSetExtensions, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
LOG: Attempting download of new URL file:///C:/Users/suren/AppData/Local/Temp/Temporary ASP.NET Files/website1/e666b402/d061aee1/System.Data.DataSetExtensions.DLL.
LOG: Attempting download of new URL file:///C:/Users/suren/AppData/Local/Temp/Temporary ASP.NET Files/website1/e666b402/d061aee1/System.Data.DataSetExtensions/System.Data.DataSetExtensions.DLL.
LOG: Attempting download of new URL file:///F:/aspnet/WebSite1/bin/System.Data.DataSetExtensions.DLL.
LOG: Attempting download of new URL file:///F:/aspnet/WebSite1/bin/System.Data.DataSetExtensions/System.Data.DataSetExtensions.DLL.
LOG: Attempting download of new URL file:///C:/Users/suren/AppData/Local/Temp/Temporary ASP.NET Files/website1/e666b402/d061aee1/System.Data.DataSetExtensions.EXE.
LOG: Attempting download of new URL file:///C:/Users/suren/AppData/Local/Temp/Temporary ASP.NET Files/website1/e666b402/d061aee1/System.Data.DataSetExtensions/System.Data.DataSetExtensions.EXE.
LOG: Attempting download of new URL file:///F:/aspnet/WebSite1/bin/System.Data.DataSetExtensions.EXE.
LOG: Attempting download of new URL file:///F:/aspnet/WebSite1/bin/System.Data.DataSetExtensions/System.Data.DataSetExtensions.EXE.</p>

<p><hr></p>

<p>Version Information: Microsoft .NET Framework Version:2.0.50727.4200; ASP.NET Version:2.0.50727.4016 </p>
