Ref: http://www.catsailor.com/forums/faq_english.php?Cat=#cookies


Might this be part of your problem?


I sometimes have trouble with the number of read/unread messages, there seems to be a bug there, or the cookie expires /grows too large. There is also a +1 bug when calculating new messages, but it's no big deal really. I usually check the dates for the last posting, and now roughly when I read the forum last.
If you use internet explorer, its default settings shuld be changed from "Check Automatically" to "Check every time" under "tools" -> "internet options" -> "general" -> "settings" (look under "Temporary internet files")