Reply To: Error in WP-File
@whiskyharry – what theme are you using? Have you tried disabling your other plugins and then see if it is one of them that is the cause?
I would manually delete everything in the wp-includes folder and re-upload a clean wp-includes folder from a fresh d/l of wp. (of course you may want to wipe and re-upload your wp-admin folder as well.
make a backup of your whole site files just in case – but you should be able to wipe and reinstall those files without any issue.