Thanks for the post and the replies: the fact that the problem
went away when people switched browsers is telling me something:
because I switched the site URL from
http://www.patrickmin.com/calcudokuto
http://www.calcudoku.org, I think there's a conflict with the "cookies"
(information the browser stores on your PC about your login session)
from the old site (patrickmin.com) and the new one (calcudoku.org)
If true, the problem should clear in about 24 hours.. (so Saturday afternoon
around 18.00 Central European Time, 10.00 EST)
Sorry for the inconvenience..
Patrick