ImageField + ImageCache = Lightbox doesn't work

Hi there,

I want to generate a gallery. For doing that I created a new content type "gallery" containing an imagefield.
The image is processed by imagecache to be shown as a thumbnail.

This is what the view looks like: http://www.rubaff.de/drupal/?q=galerie

The view is showing the correct thumbnails, but as soon as I choose "lightbox" in any way as an option in the view or the node itself, no image is shown: the source-code content-area is empty!

Thumbnail-creation and showing the image is not a problem.

Any ideas are appreciated!

Thanks!