There are several different reasons that it would happen:
It hasn't been 24 hours after you have logged in the last time and the counter was not reset for you. In this case you have to wait until it is 24 hours after your previous log in.
You have a web-surfing accelerator active on your computer or your browser have that feature (usually called pre-fetching or offline browsing). In that case you must turn it off otherwise you'll always get that message.
Your browser did not log you in properly. If your browser's cache setting is too aggressive, it may not fetch the login page from the site. That means the site does not really know that you officially logged in. What you need to do is to change your browser's cache setting to check for new pages 'every time' with each visit to the page. Then clear your browser's temporary internet files. That should solve the problem for you.