As this doesn't seem to be a generally reported issue, have you tried clearing your local browser's cookies to see if they have somehow got messed up? If you just clear the ones relating to the DIS that would save any issues with any saved settings you have for other sites. Alternatively, if you don't want to do that, could you temporarily try a different browser (it's quick and free to install a copy of Firefox, Chrome, Safari, etc) and see if you have the same issue there?
Andre