I created my own custom post type using Custom Post Type UI.
But whenever I save (publish or save already published post types) one of them the page goes blank showing only "-1" (source code is empty too). I was able to create new entries a drafts.
All changes I make during editing one entry are saved (reloading the front view of the current entry).
Then I deleted this post type and created my own one basically using this tutorial http://net.tutsplus.com/tutorials/wordpress/rock-solid-wordpress-3-0-themes-using-custom-post-types/. The error keeps the same.
Regular posts and pages are not affected.
I checked my code and the functions.php, but besides adding my own custom post type I did not change anything.
What can be the problem? I really hope you can help me. Thanks in advance.
Edit: Needless to say that I already checked deactivating Brightbox - the error was gone.
Another thing I noticed: the URL after saving does not contain the post ID and the message, like "post.php?post=123&action=edit&message=1", it ends with "post.php".