I had many problems after moving my site and it looks like they were almost all session-related. The site wasn't storing cookies properly. I've got mine working normally now with the following fix:
I added the following to the top of eshop-widget.php, right under the first <?php tag
Obviously you need to replace WEBROOT PATH with your full site root (for example: /home/fhlinux/example.com/user/htdocs/cgi-bin/tmp). You can replace 'cgi-bin/tmp' with whatever directory you want to store the session cookies in. Make sure this directory has CHMOD permissions set to 750.
The reason this was put in eshop-widget.php is because this file is loaded on every single shop page, this ensures that the session instruction is also loaded on every single shop page.
Hope this helps.