The Kunena team has announce the arrival of Kunena 7.0.4 [K 7.0.4] in stable which is now available for download as a native Joomla extension for J! 5.4.x/6.0.x. This version addresses most of the issues that were discovered in K 6.2 / K 6.3 / K 6.4 and issues discovered during the last development stages of K 7.0
We'll begin by asking for the information that you did not provide with your request for assistance:
What version of Joomla are you using and what Joomla site template are you using?
What version of Kunena are you using and what Kunena template are you using?
Do these problems occur all the time? When you login to your website do you see these problems?
What changes have you made to your Kunena configuration settings? Have you checked our recommendations w.r.t. how you might set these things?
What other software do you use (particularly for registering users and for logging in), have you tried to integrate these with Kunena and what versions of those other extensions are you running?
Have you looked at the support forums for other software that you are using to see if there are any known issues with them?
Have you tried searching these forums here (at Kunena.com) for other topics that might involve your "you do not have permissions to access this page" matter?