Error when installing 1.80 locally

have downloaded the No Sources veriosn of 1.80 - when i attempt to open the install.aspx file in a browser i get the following warning

"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: Theme 'Install' cannot be found in the application or global theme directories.

Source Error:


Line 1:  <%@ Page Language="C#" Inherits="NopSolutions.NopCommerce.Web.Install.InstallPage"
Line 2:      Theme="Install" CodeBehind="install.aspx.cs" %>
Line 3:  


Source File: /Install/install.aspx    Line: 1 "

can anyone tell me what i am doing wrong?