OK so I removed that line of code, and the error code at the top of the page has now disappeared, however, that hasn't rectified my problem of the upload not being available. This is on the update page. See image attached.
There is a problem on the insert page too. I have html editor applied there and the upload tab works to a degree, but the link tab has the browse button which when it is clicked it opens a new window but the page cannot be found!
I've checked the files created by html editor, and they all seem to be present, so I have no idea about how to rectify this.