The remark about changing the e-mail address made me think about something else. What if they just check your ip-address to determine your country?
I have checked this by using
www.hidemyass.com (found after a quick google search). And indeed, using this site to open the Fictionwise website the verification links on my bookshelf are gone, and I can download all my books again

. So it seems the new bookshelf verification is linked to your ip-address.
As I do not know how safe this site (
www.hidemyass.com) is, I have changed my Fictionwise password. But is seems the workaround for the new verification is using a service like this, or a proxyserver, so that Fictionwise detects a USA ip-address.
Can anyone recommend a service of proxyserver to use for this purpose?