Thanks for that historical reference clarification. I've been stuck in a major Classic ASP project for years and am now jumping into ASP.NET deeply for the first time. Yes, the line that causes the error is:
<%
@ Control Language="VB" AutoEventWireup="false" CodeFile="~/admin/Skins/skin.vb" Inherits="DotNetNuke.UI.Skins.Skin" %>
So, I gather from what you say that if they recoded skin.vb for ASP 2.0 this problem would go away. In the Install package, there is no actual module in admin/Skins called skin.vb; it exists only in the source package and is the only .vb module there that is not an .ascx.vb file. I had a quick look at the source for skin.vb but don't yet know enough about the differences between ASP 1.1 and ASP 2.0 coding to see evidence of what you are talking about. However, it does sound plausible.
If that is the problem, is that not a bug? Should we report it?