Re: Hello! I have the Acrobat XI test version installed, got the registration Mail and confirmed it. When i have the program opened and try to convert the file from a pdf to a word and press the convert button, it shows a the message "application failed"

Are you sure you are using Acrobat to convert, and not Adobe Reader via ExportPDF?

I do not know of any "convert button" on Acrobat; it is usually File | Save as Other to convert to another file format.

If you are using Acrobat, can you post a screenshot of that "convert button": https://forums.adobe.com/thread/1070933