.Net Error: System.IO.Directory.GetDirectories($, $, searchoption);

in .JS I try to get string and string[] using GetDirectories, var path1 : String[] = System.IO.Directory.GetDirectories(Application.dataPath, title, System.IO.SearchOption.AllDirectories); i have this error: No appropriate version of 'System.IO.Directory.GetDirectories' for the argument list '(String, String, System.IO.SearchOption)' was found. msdn page: [Directory.GetDirectories Method (String, String, SearchOption)][1] [1]: http://msdn.microsoft.com/en-us/library/ms143314(v=vs.110).aspx