Access denied as site administrator and even journal manager

i have been finding it difficult to log into the journals as site administrator or as journal manager.
It pops up “javascript alert” “access denied”
Please I need help to work on the site and journals.

This sounds similar to:

There it seems the solution was to upgrade to OJS 3.0.1. If you are already at 3.0.1, you might follow up on that thread with more details about your experience.