Realpath errors when using imagecache presets in Views

Hi,

I'm running into a strange problem when using the imagecache presets in views. When loading a view, which uses imagecache presets (like xxx linked to image), Drupal outputs the following errors:

# warning: realpath() [function.realpath]: Unable to access /[sitepath]/album/imagename.jpg in /[sitepath]/www/includes/file.inc on line 182.

This only happens the first time, so before the actual are added to the cache. After the images have been generated, I don't see this error again (but they reappear when I flush the cache).

Now the strange thing is, when I don't use the presets, but use a link to the image like

everything works just fine.

I'm a beginner with Drupal, so hope someone can help me out! I'm using PHP 5.2.4-2ubuntu5.7 with public file transfers.

Thanks.