Hello everybody. After updating the plugin, here is the error I receive in my console when the event starts:

(05:07:22) | Failed to call hook 'ccmdDangerousTreasures' on plugin 'DangerousTreasures v1.3.4' (FormatException: Index (zero based) must be greater than or equal to zero and less than the size of the argument list.)
 at System.Text.StringBuilder.AppendFormatHelper (System.IFormatProvider provider, System.String format, System.ParamsArray args) [0x000ff] in :0
 at System.String.FormatHelper (System.IFormatProvider provider, System.String format, System.ParamsArray args) [0x00023] in :0
 at System.String.Format (System.String format, System.Object[] args) [0x00020] in :0
 at Oxide.Plugins.DangerousTreasures.msg (System.String key, System.String id, System.Object[] args) [0x00134] in <4ee79308c2bd49efbf25a286620f578c>:0
 at Oxide.Plugins.DangerousTreasures.TryOpenEvent (BasePlayer player) [0x005a2] in <4ee79308c2bd49efbf25a286620f578c>:0
 at Oxide.Plugins.DangerousTreasures.GetNewEvent () [0x00000] in <4ee79308c2bd49efbf25a286620f578c>:0
 at Oxide.Plugins.DangerousTreasures.ccmdDangerousTreasures (ConsoleSystem+Arg arg) [0x0026b] in <4ee79308c2bd49efbf25a286620f578c>:0
 at Oxide.Plugins.DangerousTreasures.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x00b47] in <4ee79308c2bd49efbf25a286620f578c>:0
 at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <33f7c42a56934dae8ec04b11017dce31>:0
 at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in :0
 at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in :0​

Thank you in advance for your help ;)

Looks like your language file was edited wrong. Likely "OpenedEvents"

yess it's ok..