E_ACT_NOT_READY

Hi, I have a new ereader and wanted to put some books on it. I have the following message when I try to put my books in ADE. I read some posts on the subject and tried to solve the problem by removing the autorization on my mac and then autorize again, but unfortunalterly it doesn't work because it says it is impossible to remove the autorization after I have entered my password... 

Who can help me with this? 

Many thanks!!!

Catherine