"The markup in the document following the root element must be well-formed." on line 3 is shown because there's no parent element to contain <title>,<questions> and <answersets>.
Wrap with <trivia> </trivia> on lines 2 / 19 to fix. Not sure if this would mean changed somewhere in the parsing code. I couldn't find the file name "triviainfo.xml" in any php file of the plugin.
This may also be the actual fix for you " * Probable fix for XML Parsing Error: no element found likely caused by memory leak
" from readme.txt changes on ver. 2.2
