Debugging is not supported under current trust level settings (??)

[dgk]

Is there a FAQ somewhere about how to publish a web app to a (2003)
server? I've mapped a drive to a directory under inetpub/wwwroot, and
used the Visual Studio "Publish Web Site" menu option to build and
publish it. The app files show up on the server. I went into IIS and
created it the app as a virtual directory. Now IIS looks good, with
the gear icon on the directory, but trying to access the application
via IE gives this message:

Debugging is not supported under current trust level settings

I have no idea what the problem is. I have it working on a test server
but trying to publish it to the production server is giving me fits.

Any ideas greatly appreciated. Here's the full page that is returned:

Parser Error
Description: An error occurred during the parsing of a resource
required to service this request. Please review the following specific
parse error details and modify your source file appropriately.

Parser Error Message: Debugging is not supported under current trust
level settings.

Source Error:
Line 1: <%@ page language="VB" masterpagefile="~/PRDUA.master"
autoeventwireup="false" inherits="_Default, App_Web_1vuq0qoz"
title="PRDUStart" %>
Line 2: <asp:Content ID="Content1" ContentPlaceHolderID="CPH"
Runat="Server">
Line 3: <div style="font-size: large; color: blue;" align="left">