Murkka wrote:I receive
"You cannot give to this user!"
sometimes, why?

Usually that should happen with users with the same IP only - so mules (In this case it should not really matter, but we had events where the user you give something to would actually get something too, so that could be easily abused with mules and I guess starkad re-used part of that code).
But sometimes users have dynamic IPs - That means that a internet provider gives out different IPs to users each time they connect to the internet and sometimes it means that you can have the same IP a different user (who possibly has the same internet provider) a different user had in the past. I can only guess, but I think that might be what is causing the message.