[stylist] off topic but important, trouble searching nfbnet archives

[vejas]

Hi,
When I go onto the Nfbnet site, and click "search the archives" 
I'm having a problem searching, which is weird because it used to 
work but now I get the message Unknown property name to sort by: 
Property 'unixdate' is not defined in index 
'/usr/local/nfbnet.org/swish/listsddnfbnet.orgddindex'



Whatever that means.
Is something wrong with the site, because I used to be able to 
search it before?
Vejas