thanks for your report. The mp3 import is a known issue - we've had to disable the old reader because of library licensing issues and are currently transitioning to another library. This should be fixed in a couple of weeks.
Wave files on the other hand should import with no problems, so we'd be very happy if you could provide the crash logs and the Wave files that produce the crash by sending them to email@example.com.
To find the crash logs go to ~/Library/Logs/DiagnosticReports/ (by opening a finder window, clicking on Go->Go To Folder... and copy/pasting the beforementioned path). It should open the folder and you should have some files in the format of
Thanks again and sorry for the inconvenience!