Upgrade from 5.4.0.5 to 5.4.2.1

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After an upgrade from 5.4.0.5 to 5.4.2.1. some functionality in the dashboard is missing.
If I click on File Manager I get nothing, just a big FILE MANAGER in the top left hand corner. Also the Add Functionality goes to a Reload page. (Server error
The website encountered an error while retrievinghttp://www.grissomtechnology.com/index.php/dashboard/install/.... It may be down for maintenance or configured incorrectly.)

Any suggestions.

davidgtdfw