New Post: Multipart argument exception

I have been trying for some time now to get multipart extraction to work. I have a folder with a two part rar, a.rar and a.r00. Heres the code I am trying to use.

var archive = RarArchive.Open(@"F:\unrar\a.rar");
  foreach (var entry in archive.Entries.Where(entry => !entry.IsDirectory))
    {
      entry.WriteToDirectory(@"F:\unrar\", ExtractOptions.ExtractFullPath | ExtractOptions.Overwrite);
    }

When I point to a single file rar archive there are no problems. When the archive is multipart I end up with this exception. Filename invalid or next archive could not be found:F:\unrar\a.rar.

EDIT: Seems somehow my rar is corrupt? Extracts with WinRar throws this exception with SharpCompress.