See http://tracker.moodle.org/browse/MDL-12572. A 1.9 patch is attached.
Quiz downloaded reports contain html markup
Tim - Reassigning this to you. Sorry for the delay but I have figured out how to have the bugs related to the detailed responses automatically assign to you now. Peace - Anthony
Closing this old bug.
The responses report is now in Moodle core, and this bug has been fixed there.