VS 2010 - Call Procedure From A Class

Inside my application I created the following class

Code:
Public Class clsProject

Public Sub AddData(ByVal cproject As string)
...
end Sub
end Class

I want to call this procedure from a sub in a form. So in the code behind file I wrote

Code:
Imports TextMgmt.clsProject
Public Class WebForm1
Inherits System.Web.UI.Page
Protected Sub btnAddData_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnAddData.Click
Call clsProject.AddData(txtInput.text)
End Sub
End Class

I get the following design time error: Reference to a non-shared member requires an object reference.I thought making things Public would make them visible.