Microsoft Web Acess for Exchange 5.5

I installed Exchange 5.5 with service pack 4 and Winnt 4.0 with Option Pack 4, with IIS 4.0 and i cant get my Microsoft Web Access to work via internet to login to my emails. The error that i am having is HTTP Login 401-401.1. I look on the Mircosoft Website and the said that i need to Installed IIS 3.0. Is this the only sloution to this problem.

Anticipatory thanks for your kind speedly corporation

Robin