[wp-hackers] Error with gallery

[André Schieleit]

Hello all,

I have on my site some pictures on a page which I display as an  
gallery via the [gallery]-tag.
When I click on a picture the picture will be displayed but above the  
picture I get an error that reads
Warning: Invalid argument supplied for foreach() in /path/to/wp/wp- 
includes/post.php on line 1908

I did find no information what could possibly be the source of that  
error. I use a custom theme. Do I need some special things in my  
theme? Or is it a WP-Bug?

   André