Odd behaviour of Z block

Zemanta is a great piece of blogging software; thanks for bringing to Drupal. I've installed it and it works ok in the default theme, Garland, but when I use it with Marinelli (n.b. not Minelli!!), which has two adjacent sidebars, the contents of the Zemanta block appear to the left hand side of the Zemanta block title and, in this case, overlay the right hand sidebar. Since the Zemanta block content is transparent, it is near impossible to utilise, as well as appearing in the wrong place and obliterating the other blocks beneath it.

Any ideas what might be causing this? I'm not fully conversant with theming, but I do understand CSS.

Thanks for any support you can provide. It would be a shame if I couldn't use Zemant alongside Marinelli, which is my chosen theme.