[Angelox]

I'm thinking if you are at the same IP of your server, you won't see any ghosting - you'll need people that log in from distant IPs and suddenly drop out.
Maybe some how this remains cached in the system and the server thinks there's someone still there, or maybe the server missed some packets with the sudden drop out.
could be they get LD on zoning, then the character arrives in the next zone, but the PC is gone.
Problem is, it's seems related to other players on your server. At one time, I remember having this problem when I ran a windows server. it was when I first started out. At the time I had a Pentium 3 with little memory and was playing on the server with the client on the same machine.
I remember seeing a lot of the ghosting effect. I figured it was related to lag , and lag created by multiple players zoning and logging in (LD).
I could play alone fine, but this would start when others logged in.
Also, I don't think this happens with multiple players on Minilogin - I think its related to the Public Login server.
Anyway, those were thoughts an ideas I had at the time, Went Linux and the problem for me ended with that. I still use a windows server for testing, but it's Minilogin, and I don't see any ghosting there.
You might want to try getting some friends to try you out on a Minilogin server.
Thing is, you can't have a solution until you can find what makes the problem, these are some things I'd try out, to see if anything were different.

Make observations when you see a ghosted character;
was it static or dynamic zone? was he zoning ? did he log? (you can find the account by the ghosted character name). See if you can find a pattern somewhere.