How To add refrence in asp.net project

Question

Dear All

I had created a setup for my project.I had two parts one web  folder other server folder when i built server it is build successfully but when i build web it shows error (Error    3    The type or namespace name 'BasePage' could not be found (are you missing a using directive or an assembly reference?)    C:\Users\h\Desktop\EcoFriendz\EcoFriendzWeb\WebPages\CommonCodeBehind.cs    13    41    EcoFriendzWeb and Error    44    The type or namespace name 'URLMessage' could not be found (are you missing a using directive or an assembly reference?)    C:\Users\h\Desktop\EcoFriendz\EcoFriendzWeb\CustomControls\Blog.ascx.cs    17    9    EcoFriendzWeb) can anyone tell me how to add refrence in bin so that these errors get fixed.