i install a new plugins in moodle and when i try to access the plugin here what happen!! :'(
Which version of Moodle and which plugin - although I assume Big Blue Button.
I'm reasonably sure that error message was not generated by Moodle - or even the BBB plugin - so it must be something to do with your hosting. Have you checked the permissions like it says? Have you asked your host's support service what it means?
Also, you might want to stick that error message into a Google search
I agree that it sounds like the permissions on the new folder and contents is probably not correct and so Moodle can't access the add-on.
I don't think it's got anything to do with Moodle at all. It'll be something like 'suexec' running on the server to prevent you running stuff with insecure permissions.