Hi,
I don't think your files are DRM protected.
Which product do you own exactly ?
I guess you bought a Numark or ION controller, didn't you ?
This version is quite old and had some bugs, but unfortunately there's no update available for your product (you may contact Numark or ION for more info).
The latest Cross DJ version (1.5.2) works without issue with these files (
without DRM !!). Check the demo out! You can then upgrade to Cross DJ and have your problems gone

Cheers,