Urg. This - http://wiki.audacityteam.org/wiki/File_Management_Tips#Avoiding_loss_of_project_audio_due_to_missing_dependent_file - is what happened.  Usually, I plug the Zoom into my computer and it's no problem, but now it's saying it's plugged into F: instead of G:.  How do I fix that?  By doing the workaround found here: http://support.microsoft.com/kb/297694. But does it work...  Yes! 

Now on to practicing...