The error EBK_DL_NOFORMAT_[followed by some numbers] means that the ebook format that you are trying to download doesn't exist in our fulfillment server.
Normally we never remove access to an ebook once a customer has purchased it. However sometimes a file needs to be removed because the publisher accidentally submitted the incorrect ebook file, or there are issues with the file that cannot be fixed. If we do this we will always then contact the publisher and ask them to supply a replacement ebook file. But until we receive the replacement any download attempt will result in this error.
To resolve the issue please contact our support team. Please quote the full error message (the numbers in your error message are important as they tell us which ebook to check). If the book is available in more than one format (EPUB & PDF) then please state which format gives the error. If one format is unaffected please download that format and use it to read the ebook, if possible, while we resolve the issue with your preferred format.
Occasionally a publisher will create a campaign which contains ebooks that are not yet published. If you redeem the campaign code it will add the ebook to your account, but when you try to download the ebook you will receive this error. Unfortunately in these instances there is nothing we can do. You need to wait for the ebook to be published or for the publisher to supply the ebook files and you will then be able to download the ebook. If you check the product page of the ebook it will display the publication date which will indicate when the ebook will become available.