Ever since i changed my computer i can't seem to be able to read my e-book bought on my other computer! HELP!

I changed computers two times, they always die on me! And each time, i can't read the e-books that i bought on my other computer! There is a message that appear that tells me that there is a problem with the license. E_LIC_ALREADY_FULFILLED_BY_ANOTHER_USER

That is what they tell me and i am going insane!