hi,
I have tested this at my end and it works perfectly.
please have a look here:
http://somup.com/cYVYlMfP4h
as you can I have imported a CSV file and then it's added in all quizzes section in wplms.
in your site, if this is not happening then maybe the prefix of your database is different.
as you can see that in CSV file the prefix is "wp_" if your prefix of the database is different then it's not going to be imported on your site.
for importing the things on your site you have to make changes in the CSV file. change the prefix with your site's prefix.
it will solve the problem.
please let us know the results.