I'm trying to add adobe connect meeting but i get this error. Can you help me ?
I don't know what the underlying cause is, but the error you are seeing appears to be a bug (or at least some rather unsafe code) in core Moodle.
I'll raise a tracker report while I think about it. Doesn't really help you unfortunately.
I would check your web server error log in case there are any other errors or warnings related to this that might help.