Error trying to buy house on property

[jopnine]

Im getting this error

[ERROR] gamemodes/medievalrp/plugins/_oldplugins-fix/sh_plugin.lua:147: attempt to call method 'getChar' (a nil value)

1. GetVar - gamemodes/medievalrp/plugins/_oldplugins-fix/sh_plugin.lua:147
2. unknown - gamemodes/medievalrp/plugins/property/sv_plugin.lua:66
   3. func - gamemodes/nutscript/gamemode/core/libs/thirdparty/sh_netstream2.lua:117
   4. unknown - lua/includes/extensions/net.lua:32

I have try change line 147 into
if var == "id" then return self:getID() end
and it works barely