Here are the compile issues:
Assets/Plugins/Pixel Crushers/Dialogue System/Third Party Support/I2 Localization Support/Scripts/Editor/DSToI2Window.cs(356,27): error CS1502: The best overloaded method match for `UnityEditor.EditorUtility.SetDirty(UnityEngine.Object)' has some invalid arguments
Assets/Plugins/Pixel Crushers/Dialogue System/Third Party Support/I2 Localization Support/Scripts/Editor/DSToI2Window.cs(356,70): error CS1503: Argument `#1' cannot convert `I2.Loc.LanguageSourceData' expression to type `UnityEngine.Object'