Add Image, add Media and HTML buttons don’t work in post editor

Hello all,

For starters, let me emphasize that I am not new to WP and am running several sites on this, my favorite platform.

The issue at hand is that the Add Image, Add Video, Add Audio, Add Media and HTML view buttons in the Post Editor don’t work. The link is displayed in the bottom left-hand corner of the browser (I’ve tried it in Firefox, Chrome and even Explorer), but there is no reaction whatsoever when I click on it. I’ve cleared my cache and browsing history, I’ve disabled all plug-ins, restarted and still nothing. I am able to open the link in a new tab, insert the image, but the results aren’t saved and have no effect on the blog post. And I can’t get into HTML view where I could easily do it in HTML. I’ve tried it all on a different computer – same problem. The post editor and buttons in question are working fine in the same browser (obviously diffrenet tab or window) on all my other sites and blogs. Below is the URL, other possibly relevant info and the plug-ins that have been activated on the URL in question.

URL: https://willourworld.com on GoDaddy
Plug-ins: NextGen Gallery by Alex Rabe
Facebook Like by Ahmed Hussein
TweetMeme Retweet Button by TweetMeme
WordPress.com Stats
Theme: Arthemia – free version (you’ll notice the theme has been modified quite a bit, but I’m told by the other admin that we had the same issue with a previous WOOthemes theme that wasn’t modified)

To be honest, I had the same problem with the same theme a while back on another URL – https://dare2speak.com and can’t for the life of me remember how I fixed it. I recall it was a permission thing somewhere.

Hope this rings a bell for someone, I’d appreciate some help!

Thanks!