How to handle Default Design errors

Imported From: http://groups.google.com/group/in-portal-bugs/browse_thread/thread/8c61cbd6b3cdb58f#

On a v510 install, used for a long time, we suddenly have, when we try to edit a category with content mode using the right little square:

Design Template: #default_design#; CategoryID: 2054 
Function: NParser->CheckTemplate <file://w:/core/kernel/nparser/nparser.php> in nparser.php on line 422
 Array 
( 
    [0] = #default_design# 
    [1] = NULL 
) 

Function: NParser->Run <file://w:/core/kernel/application.php> in application.php on line 1077 
 Array 
( 
    [0] = #default_design# 
) 

Function: kApplication->Run <file://w:/index.php> in *index.php* on line 21
 
 
Fatal Error: Cannot include "*#default_design#*" - file does not exist in *...\core\kernel\nparser\nparser.php<file://w:/core/kernel/nparser/nparser.php> on line 392

how can we make this default file existing? Is there anything to write in default_design.des.tpl file comments (we are using advanced theme)
how to use the field [10.03] cms_DefaultDesign ? I've tried to indicate the full path platform/design/default_design but no luck