You can upload an ePub file for distribution. If you do, please make sure the ePub file passes an ePub check. A good validator can be found at http://validator.idpf.org/
It is very important that none of the individual files inside your ePub have spaces in the file names or contain images that exceed 4 million pixels (length multiplied by width). Otherwise we will not be able to deliver your ePub file to any of our retail partners. Not every ePub validation tool scans for this so please check your ePub file carefully.
If you have any questions please contact our publishing support team at 877-961-6878.