[Jeff Sayre]

@Mohit

Perhaps Burt or John will have a different take on this, but since you have the helper plugin installed and are still having this issue, then it could be an issue with an outdated libxml library.

Which version of libxml2 and PHP is your server running?

If it is not what is recommended in that article I linked to in my first post, then you might want to upgrade and see if that solves the problem.