Importing songs fails with little information

Steps to reproduce

1. Visit the page to add content
2. Try to import one or several OGG files
3. Submit

What happens?

Upload works but import fails, with just an error message about the tags: "An error occured while processing this track, ensure the tracke is correctly tagged"

I've removed some tags to the files I tried to upload, using only tags I'm sure at allowed, but had no luck. All the files have that very same error, but no information on how to solve the tags problem.

What is expected?

Import should be successful if the file is well formed. If the file is badly-formed, an error should point out what the reapl problem is so the user can fit.

Test files (CC-BY license)

Example of file I tried to upload: 20150427_-Nazrock-Zombie__The_Cranberries_cover.ogg

A modified test file with simple file name and minimal amount of tags: test.ogg

Both fail wit the same error message as explained above.