A* on Winphone8.0 error

hi
When i use A* Pathfinding on WP8.0 , i get this:
System.MissingMethodException: Method not found: ‘Void System.IO.File.SetAttributes(System.String, System.IO.FileAttributes)’.
at Pathfinding.Ionic.Zip.ZipEntry.InternalExtract(String baseDir, Stream outstream, String password)
at Pathfinding.Ionic.Zip.ZipEntry.Extract(Stream stream)
at Pathfinding.Serialization.AstarSerializer.GetString(ZipEntry entry)
at Pathfinding.Serialization.AstarSerializer.DeserializeMeta(ZipEntry entry)
at Pathfinding.Serialization.AstarSerializer.OpenDeserialize(Byte[] bytes)
at Pathfinding.AstarData.DeserializeGraphs(Byte[] bytes)
How can i fix it?

Hi

Have you followed the instructions for Windows Phone here: http://arongranberg.com/astar/docs/iphone.php?