Hi,

Im trying to show all albums and their sub albums in index.php.

I have tried to use the "while (next_album(true).." loop, but it only show the top level albums. What am I doing wrong?

That is how it is supposed to work. You have to use the object model within the loop instead:
http://www.zenphoto.org/news/zenphotos-object-model-framework

Quick example to get the title of a subalbum within the loop:
$subalbs = $_zp_current_album->getAlbums(); foreach($subalbs as $subalb) { $obj = newAlbum($subalb); echo $obj->getTitle()." "; }
This of course gets only the next sublevel.