error on a hidden column in my grid

error on a hidden column in my grid.

var grid = new dhtmlXGridObject('gridbox');
				grid.setImagePath("vue/dhtmlxGrid/codebase/imgs/");
				grid.setHeader("Mode de transport,Départ,Destination,Cout");
				grid.setInitWidths("200%,200%,200%,200%");
				grid.setColTypes("ed,ed,ed,ed");
				grid.setColAlign("center,center,center,center");
				grid.setColSorting("str,str,str,str");
				grid.setSkin("dhx_skyblue"); 
				grid.init();
				//alert(grid.getColumnId(2));
				grid.setColumnHidden(2,true);

i have the following error:
TypeError: grid.setColumnHidden is not a function
grid.setColumnHidden(2,true);

setColumnHidden() method is available in PRO version only:
docs.dhtmlx.com/doku.php?id=dhtm … lumnhidden