The Topic does not load - you see a black screen with red text "Topic is loading...Please wait."
This is most likely down to a compatibility issues between UPK, Internet Explorer, and Windows (versions of each vary). Check your IE compatibility settings (Tools | Compatibility View settings), and change the Display intranet sites in Compatibility View settings. If it is set on you may need to set it off, and vice versa, depending on your software versions.
This issue is not known to occur with Google Chrome.