Cannot use a leading .. to exit above the top directory

I'm converting a VisualStudio 2003 solution to Visual Studio 2005 (using C#) and changing multiple hard-coded pages to use a Master Page. It all looks fine, but when I go to debug, I keep getting the above exception and it is pointing to this statement in my Global.asax.cs file:

        protected void Application_AuthenticateRequest(Object sender, EventArgs e)
        {
FIMGlobal.FIMGlobal.Application_AuthenticateRequest(Request,Response,"14","~/DeptDeposit2005/Main.aspx","Acess denied for Dept Deposit");
        }

This is a reference to the following part of a dll:
public static void Application_AuthenticateRequest(System.Web.HttpRequest Request, System.Web.HttpResponse Response, string sAppID, string sURL, string sMsg)
    Member of FIMGlobal.FIMGlobal

However, even when I go through and replace every last ../ with ~/ or even take it out completely (just for fun) or send it directly to the location of that page, it gives me the same error on the same line.

I've spent three hours looking through sites with that search to no avail. Doesn't matter where I move the folders on what machine, I get the same thing.

Any help would be GREATLY appreciated!