When you invite someone next to you, you can't see him. You need "teleport" in one of the istanced places and go back, after that you can. i dont know why
For me the problem is the pvp that is used today in mmo. We could not find anything like Ultima Online and lineage 2. Always arena and bg, this is bs man! And Neverwinter will be the same thing, I'd really like a place where we can level up and pvp at same time, one place at least.