5.6.4.0 - Unable to access dashboard features

Permalink
After upgrading to v5.6.4.0 I am unable to access many of the dashboard features. For example: when accessing the "properties" of a page on the site map, the popup form is disabled except for a "close" button. This occurs in many other areas of the dashboard also. My account is a member of the administrator group. I tried using a new administrator account also. I have attached a screenshot. Please help!

1 Attachment