[thelist] tier referencing - (.net, c#, web ap)

[Lightning]

I am having a problem referencing a tier from a web page.

My page, WebLogin.aspx, has as using "using BusinessTier;" (I have also 
tried refixing with solution name as in: "using WebLogin.BusinessTier;" to 
no avail.)

I have added BusinessTier as reference to the WebLogin project.

I get compile message "The type or namesace name 'BusinessTier' does not 
exist in class or namespace 'WebLogin'. Are you missing an assembly 
reference? "

The BusinessTier in turn uses a DataTier, and this connection is working.
One thing I notice is that dll's have generated for the data tier, but not 
for the business tier.

QUestions:
1. what software will read the dll's (I have tried many.)
2. How can I create/generate the proper dll's for the business tier?
thanks you
Laura