cannot create temp wave file

I’m trying to use an external editor with H5, but whenever I try to send a sample over to it, I get the message “Cannot create temporary wave file.” I’ve tried assigning different folders for the temp files and none of them have permission problems or anything like that, so I can’t figure out why H5 is having trouble. Does anyone know what might be going on?

Halion 5.1.1.60
Mac OS 10.10.5