TerrainComposer Error Unity 5: DirectoryNotFoundException: Could not find a part of the path...

Hi I have a problem with " terrain composer" . The problem is the following:

DirectoryNotFoundException: Could not find a part of the path "C:\Users\ariel\Desktop\Pruevas rust\Assets\TerrainComposer\Download\TerrainComposer_Examples5.0.unitypackage". System.IO.FileStream..ctor (System.String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, Boolean anonymous, FileOptions options) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.IO/FileStream.cs:292) System.IO.FileStream..ctor (System.String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize) (wrapper remoting-invoke-with-check) System.IO.FileStream:.ctor (string,System.IO.FileMode,System.IO.FileAccess,System.IO.FileShare,int) System.IO.File.Create (System.String path, Int32 bufferSize) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.IO/File.cs:135) System.IO.File.Create (System.String path) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.IO/File.cs:130) System.IO.File.WriteAllBytes (System.String path, System.Byte[] bytes) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.IO/File.cs:594) TerrainComposer.check_content_done () (at C:/Users/ariel/Downloads/AU FPS KIT v1.5/Pruevas rust/Assets/TerrainComposer/Editor/TerrainComposer.js:15896) TerrainComposer.OnInspectorUpdate () (at C:/Users/ariel/Downloads/AU FPS KIT v1.5/Pruevas rust/Assets/TerrainComposer/Editor/TerrainComposer.js:336) System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:222) Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation. System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.Reflection/MonoMethod.cs:232) System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.Reflection/MethodBase.cs:115) UnityEditor.HostView.Invoke (System.String methodName, System.Object obj) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:187) UnityEditor.HostView.Invoke (System.String methodName) (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:180) UnityEditor.HostView.OnInspectorUpdate () (at C:/buildslave/unity/build/Editor/Mono/HostView.cs:145)