Failed to call hook 'OnBetterChat' on plugin 'BiomeChatPrefix v1.0.0' (KeyNotFoundException: The given key was not present in the dictionary.)
  at System.Collections.Generic.Dictionary`2[TKey,TValue].get_Item (TKey key) [0x0001e] in :0
  at Oxide.Plugins.BiomeChatPrefix.OnBetterChat (System.Collections.Generic.Dictionary`2[TKey,TValue] data) [0x00000] in :0
  at Oxide.Plugins.BiomeChatPrefix.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x001ca] in :0
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <9affce1cd15c4ec183941adef8db1722>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in <4452f821def6406d834e4149849fe7ea>:0
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in <4452f821def6406d834e4149849fe7ea>:0

This should be fixed now.