When you say Adobe 11, does that means you are referring to the Adobe Reader 11 application?
If yes, then in order to use the services you need to upgrade the application to the latest version of Adobe Reader which is Adobe Reader DC.
You can download the Adobe Reader DC from- Adobe Acrobat Reader DC Install for all versions
You can also refer to the forum threadBought ExportPro Subscription but still can't export PDFs to Word docs where similar issue has been discussed and resolved.
Let us know if it doesn't work for you.