Type Exception is not defined; Visual studio 2010

Hi,

I am pulled into a new project where they use Visual studio 2010 (framework 4.0). I got the latest version off TFS, and tried to build the app. I get errors like "Type Exception is not defined" and "Type Datatable is not defined"; these statements belong to classes in APP_Code folder. To get rid of these error locally i could write Imports System.Data or Imports System and get awat with it. But its a solution on TFS and latest version is supposed to work the way it is.

I checked web.config file it has all the namespaces and assemblies (following is partial code)

I even right clicked the properties of web site and checked references; they are all there....

<namespaces><clear /><add namespace="System" /><add namespace="System.Collections" /><add namespace="System.Collections.Specialized" /><add namespace="System.Configuration" /><add namespace="System.Data" />
........

<add assembly="System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" /><add assembly="System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" /><add assembly="System.Configuration, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" /><add assembly="System.Net, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" /><add assembly="Microsoft.ReportViewer.Common, Version=9.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" /></assemblies>

so, I am not sure how to build my solution (without adding Import statements) ?

Any ideas?

thank you