Where are you getting these errors? New posts?
for me its anytime i log in, it goes to the "thanks for logging in, please hit this button if your browser does not automatically redirect you" page; then when it finally redirects i go to a page that shows the "you do not have permission to access this page" error.
for me it doesn't seem to matter where i am on the forum as soon as i log in i get the error page and have to click the forums page and start again from there.
Clear as mud, yet?, thoughts to text is not my strong suit but i think i explained the steps i am seeing correctly.