Hi Markl,
Looking at your requirement, Acrobat DC would be the best application for the PDF file conversion. Your account information says that you have you already purchased the Acrobat DC.
As mentioned that you are getting do not have permission message while conversion, so there couldn't be a possibility that the pdf file that you are trying to export is a secured file for which you don't have the permission.
You may try the following steps to check-
1- Try converting a different pdf file and see if that works or gives the same error.
2- Open the same file and right click on it>Document Properties>Security>Page Extraction (Allowed or not)
Regards,
Akanchha