fatal error on start!

I recently moved our blogs from an external vendors server to an internal server.

I installed a new install of WordPressMU on the new server.
Copied all the old server files to backups & restored them on the new server.
I updated the wp-config file to define the new url & home.
I updated the db table (wp-options) & home field to reflect the new internal address.

Now I when I start the blog from home, it goes immediately to this page & shows the following error:

https://10.10.240.111:22/pub/res/blogs/wp-admin/install.php
===========================================================

Fatal error: Call to undefined function is_site_admin() in /export/home/content/xxxxxx.xxx/htdocs/pub/res/blogs/wp-includes/capabilities.php on line 922

Any HELP would be appreciated…

Evans