ADE cannot open new ebooks after installing new PC

I have bought a new PC - Windows 10. I have downloaded ADE and authorised the PC. I bought a new book and downloaded to PC. ADE cannot open this book. I get the following error message:

"Unable to open "xxxx"(title of book)

Errors were encountered in this item

file:///C:/Users/ASK/Downloads/......(details of filename)

Is it Kobo, Adobe or me?