Sorry for errors in describing the error:)
Befor I change the <customErrors="remoteOnly /> element to <customErrors="off" />, the error message says I should use <customErrors="off" /> to see the detailed error message.
I use the following steps to install the sample site.
1. Unzip all files from the install package to C:\inetpub\dotnetnuke.
2.Set the default web site's root directory to C:\inetpub\dotnetnuke, and set the permissions for network service account.
3.Delete the default web.config file
4.Rename release.config to web.config, and change the connection string to connect to a SQL2005 database.
5.Open the site using http://localhost, and the install progress does not report any error.
6.Reopen the site using http://localhost, the new site works.