error/quiz/importerror

From MoodleDocs

An error occurred importing the file. The error should be noted on the same screen as the error message. Likely problems are format errors in the file or types of questions that are not supported. Note also that exporting quizzes from Moodle and then attempting to re-import in older versions of Moodle is not guaranteed to work and may produce this error.

If you are confident that the error is minor, you can set "Stop on error" on the import options tab to "No" and try again. Any good questions will be imported regardless of errors found.