Did you import the Items into the Item Maintenance cards? Is the Item window a modified window? Did you set the default sort order using another tool, or have you set a 'default' view on the lookup window? If you use the standard GP lookup window, do the items show up? For some reason you need to cause the lookup script to run in order to populate the scrolling window. What's different about your live company from Fabrikam.
Kind regards,
Leslie