Got this error on a project working on and couldn’t quickly resolve the issue. It was happening when logging into the Content Editor only and with “Standard Fields” enabled so was a tricky one.
Thanks to Sitecore 6.4 now working within Firefox.

What i did to resolve the issue was;
- Open Firefox
- Open Sitecore and login as admin in Desktop user
- Open your Sitecore Control Panel (sitecore bar/control panel)
- Preferences
- Change your application preferences
- Make sure “Fields from the Standard Template” is off and click ok
- No open the “Content Editor”
- Click on the “Home” item (default one supplied by Sitecore)
- Click Presentation tab
- Hit “Reset” in ribbon and continue
- Now Click on another item somewhere even “Content”
- Click “View” from ribbon and enable “Standard Fields”
- Now click on the “home” item and it should now load
What the issue seems to be is a reference to a layout, rendering, sublayout etc.
Hope this helps someone.