You do not mention what e-book hardware you are trying to use. The Kindle certainly isn't a supported platform. The Sony Reader might be since it says it supports Digital editions. You might try to ask in the Digital Editions forum. This is more their area of expertise:
I use the Sony Reader, but the "Digital Edetions"-software do not support documents with this security system. Does that mean, that I cannot read those books on my Sony Reader?
Thank you for answering that quick!
You may ask the provider of the ebooks.