Hi Zoomsurlille, I’ve managed to resolve the problem with the help of another developer. For me it was another plugin (NextGen Galleries) which was clashing with the og:type properties Facebook was trying to read. So I deleted it.
Now when I enter the required link into the Facebook Object Debugger and ask it to Fetch New Scrape Information, it reloads up the missing meta data allowing me to paste the URL into my Facebook page.
Hope this helps mate.
DC.