As Peter said, Apple DRM is not compatible with Kobo (or anything other than an Apple device for that matter). AFAIK there is no way to remove the DRM so that it could be used on a different device. Kobo will use Adobe DRM'ed e-pubs natively (most e-pub's except from Barnes and Noble) or if you remove the DRM from the books you purchase you can use e-pubs from anywhere (including B&N) or use Calibre to convert other formats (i.e. Amazon) to e-pub that will work on the Kobo.
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