"Finding sort keys" error

[Josef Oswald]

Has anybody else experienced this strange behavior:
One group ( comp.emacs.xemacs) I cant access any longer. 
Every time when I enter the group with RET I get the message 
Finding sort keys, and this goes on for a long time, until I hit C-g to
quit.

Some Articles in it I had marked as _/ticked/_ and after copying them to
a local folder I removed the mark. UN-subscribed the group and shut down
gnus. Subscribed again the error occurred again.

thanks for any hints :-) 
 
Josef Oswald also -> gnus@chello.at  :-) 
-- 
Gnus gives you all the opportunity you could possibly want for
shooting yourself in the foot. 
--from the INFO --