I have a similar problem going on. I don’t think my experiment was able to access the zip file properly. I followed the instructions in the documentation and uploaded a zip folder containing audio files(.WAV) to a school server along with the .htaccess, which the IT department said should work, but now I’m not really sure what’s going on. The debugger didn’t mention any type of error occurring as it was running the experiment.
It appears that this URL is not a direct link to the zip file: you need to login onto the UMichigan portal before you can access the file. Not sure what the IT department told you, but this link clearly won’t work with PCIbex (or anything else for the matter, since access is password-protected). In addition to the CORS setup, you want to make sure you have a link that directly gives you the zip file when you use it in a new, private navigation session in your browser.