How to save on a relative path?

I have the following method:

private string SubirImagem(string imagemupload, string sequencia, string clifor)
{
    HttpPostedFile imagem = Request.Files[imagemupload];
    string nomeimagem = "";

    if (imagem != null && imagem.ContentLength > 0)
    {
        string extimagem = Path.GetExtension(imagem.FileName).ToLower();
        nomeimagem = clifor + '_' + sequencia + extimagem;
        imagem.SaveAs(Server.MapPath(Path.Combine("/Uploads", (nomeimagem))));
    }

    return nomeimagem;
}

Location this method is working normally, hosted it is presenting error reporting that I am not allowed to write to folder:

  System.UnauthorizedAccessException: Access to the path "hijackserver" \ httpdocs \ Uploads \ 510247_1.png is denied.

Would you like to know how to save on a relative path? Or some other way to do the above method.