Hi,
I have just created the identical directory structure on my dev server can copied over all my production box expression engine folders and exported the db. The only thing that has changed is the URL When I first launched the dev url the site loaded fine. I logged into the CP and changed the urls in the general settings. I test the url again and got a white screen of death. I change the settings back and still get the white screen. This is the log entry error
PHP Fatal error: Call to a member function user() on a non-object in /datastore/ee/system/core/core.functions.php(634) : eval()‘d code on line 6
ExpressionEngine 1.6.8 - © Copyright 2003 - 2009 - EllisLab, Inc.
Script executed in 0.1624 seconds 15 SQL queries used
Build: 20091002