This error message does not originate from Adobe Digital Editions (ADE). Instead you can get this error message from attempting to open your URLLink.acsm file in Adobe Acrobat or Adobe Reader.
There is an Adobe DRM plugin called ebook.api for Acrobat Reader and Adobe Acrobat that allows them to open .acsm files. But it is only compatible with PDF files, not EPUBs.
We do not recommend using this plugin as it does not support the majority of the ebooks available from eBooks.com (EPUBs). Also to date we are yet to find a solution to this error.
We strongly recommend installing and using Adobe Digital Editions (ADE) instead as it supports both PDF and EPUB file formats, and it is easier to provide support for.
If you have any difficulty opening the file in ADE please contact our support team. Please quote the error message you last received when doing so.