Crash when login with client on linux

[Carlossg]

Oh come on people. WHY does everyone say "oh it writes SOME error in the console" all the time?
HOW am I supposed to fix it if you don't tell me exactly what the error was, so that, you know, I can find it?

Sorry;
[20:07:15] LUA: 2 - Plugins/Core/functions.lua:151: attempt to index global 'Player' (a nil value)
[20:08:44] *** Window lost sync at item 15 in SlotArea with 27 items ***
[20:08:44] My item: -1:0:0 * 0
[20:08:44] Their item: woodendoor:0 * 1
[20:08:46] *** Window lost sync at item 14 in SlotArea with 27 items ***
[20:08:46] My item: -1:0:0 * 0
[20:08:46] Their item: woodendoor:0 * 1

I don't know if the first one is related with the last one.

Ah, sometimes I see that he have a object and he is using other one(Example, I see wood, but he is using a peak) but I don't care about this