You receive an "Update Error" status on the Administration - Version - Updates page of the Control Center when doing the following:
1. Click the Check for Updated button.
2. Select the radio button next to the version available for update.
3. Close the description page.
This is a cosmetic error and does not impact your ability to update. Selecting to install the version available will continue with the update. This has been fixed in 10.5.1 going forward.