ArcGIS Engine栅格计算使用IMapAlgebraOp 接口一直报错如何解决？

如题，ArcGIS Engine栅格计算使用IMapAlgebraOp 接口，出现如图所示错误


代码如下：
IMapAlgebraOp rstcal = new RasterMapAlgebraOpClass();
            IRasterLayer rstlyer = GetRasterLayer(Convert.ToString(comboBox1.SelectedItem));
            IRasterBandCollection bdcol = rstlyer.Raster as IRasterBandCollection;
            IRasterBand rband = bdcol.Item(0);
            string fullname = Convert.ToString(comboBox1.SelectedItem);
            int index = fullname.IndexOf(".");
            string rstnm = fullname.Substring(0, index);
            rstcal.BindRaster(rband  as IGeoDataset,"rst01");
            string excute = "[rst01]/4";
            IGeoDataset gd = rstcal.Execute(excute);