Adding reference to DLL is not working

I have created a VB DLL by selecting File - New - Project and then Class Library
I added a "Properties" region and a "Function" region with some simple properties and one simple function. Compiled it and used it in another app with no errors.
At that point the only references in the project were the default references when creating the new project.
I then created a function that will take a file as a param and get the physical path and add the 2 together. In the function I use the "Request.PhysicalPath" method of the System.Web.UI.UserControl.
I then added areference to the System.Web DLL in my project.
PROBLEM IS I get an error on "Request" that says "Name Request is not declared"
So I googled the error which I found a thread that said to "just use HttpContext.Current.Request.Form" because "by default all websites developed in Visual Studio 2005 is In ...