Can I move a system database from one version of SQL server to another? We are moving our databases from one computer running SQL Server 2005 to a different machine running SQL Server 2008.

I am following the steps found here, in an attempt to copy over the master database, with all the user logins and server-level permissions, however it is telling me the backup cannot be restored because it was created by a different version of the server.

Is there a way to copy the master database from one version of SQL server to another version of SQL server?
No you can not move the master database (or any system database) from one version of SQL Server to another version of SQL Server.  You would need to install SQL 2005 on the server, then restore master.  Then upgrade to SQL 2008.