Multiverse Problem! Fast please

I've got a problem now. I did install PlotMe + Multiverse + Multiverse Inventory.

Now when a old player joins it says "Welcome this new player" and all his items are gone. If he had Diamond set, diamond tools and such it will be gone. He will have to start over from the start..

I don't want that. I put the server to white-list to fix this problem but I can't find anything.

Can somone help me?