URGENT Forum Broken (session verification failed)

[Harry33]

Just yesterday, I started getting this when I try to log in or out of the forum An Error Has Occured! Session verification failed. Please try logging out and back in again and then try again it continues all the time
When I try to post a message I get this error:
the following error or errors occured while posting this message:
Your session timed out while posting. Please try to re-submit your message. you get the same error even if the message is submited a thousand times.
NOTE: I don't use mod
2. Members face the same issue
3. I have installed a fresh copy of sources/post.php
4. I did't try tweaking things but the problem was sudden
please what is the best way to resolve this? Thanks

[Illori]

in admin -> server settings -> cookies and sessions enter a new name for your cookie name save and relog into the forum and see if that helps. this will force all members to login new into the forum

[Harry33]

Thanks that helps. But now things has moved from worse to bad, now those error message don't show but when you try logging in and out, a blank page appear. Now when you try submit a post, a blank page appear, not knowing the page has been submitted until you hit forum URL homepage on browser. The same thing goes to login and logout issue. Not until I hit forum url again, before I see myself logged in. What next should I do please?.

[Road Rash Jr.]

Hey Harry, I see you are using SMF 2.0 RC3 and all your templates are screwed. Something has changed to cause this and it would be impossible with limited information to figure out what.
I would suggest you download the large upgrade file and install it. That will give you the lastest version and fresh files that should fix your problem.