The forum server/domain was changed; any old links to "lariancom.siteprotect.net" just have to have that part of the URL changed to "larian.com" to work properly.

Lost Items - guide and directory of inventory files

Did you backup your inventory files and restore them, in the save you were trying to get another teleporter stone set? Even if you didn't, if you used an inventory set from your own game, it shouldn't cause items to disappear in areas you had not gotten to in either save.