C# building process in Unity Crack

Hi! 

I’m cracking the apk made with Unity now,and unfortunately in the stage of buiding Assembly-Charp.dll one error occured. This is as follows.

Error 10 The type ‘System.Xml.XPath.IXPathNavigable’ is defined in an assembly that is not referenced. You must add a reference to assembly ‘System.Xml, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’. 

I already added System.Xml.dll file to the reference.

A lot of errors was repaired, there’s one left. Please help me!