[themes] core compatibility

[Lists]

We're seeing a weird problem in our Drupal themes administration.   
We've used Deco as a starting point for a customized theme.  We then  
copied this theme to a new directory (in sites/all/themes) called  
ourtheme.  We modified the deco.info file to list "ourtheme" as the  
theme name and saved it as ourtheme.info.  We also made a new  
screenshot.png.  The trouble is, in the themes list in administration  
the list shows "This version is incompatible with the 6.2 version of  
Drupal core." and lists no theme name.  We can select it as the  
default theme but it still shows no theme name in the configure theme  
page/  Ideas?