Why you are getting that error is that the yahoo 
sites give a temp cookie when you log in which is 
used to identify you for logging into your my page 
, for viewing auctions (you still will need to 
enter your password to actually place a bid), etc. 

I believe the translations programs will either 
not send the cookie or the temp cookie is erased 
when you log into the translation program. This in 
effect causes you to have lost your log in and 
thus to appear to the yahoo server as an 
unregistered observer with no cookie when trying 
to read their site. Which means its time to start 
learning Japanese or translating it the hard way 
if you want to translate finished auctions or bid 
confirmation.

Marcus