Logging out from the Active Roles Web Interface and refreshing the page, IE breaks, it pops up with an odd Authentication box. If instead the URL last bit, “Misc/logout.ASPX”, is removed, and the page is refreshed, it breaks the ARS site too:
When the prompt shows up after logging out, instead of typing a password right there, click "More choices" and then select "User a different account". This will give the input for both username and password.
Closing out the browser and re-opening it also clears it up.