Dhtmlxgrid with dataprocessor can not send data

Hi guys,

I have a dhtmlxgrid with a dataprocessor. When I update a cell, I have error [Uncaught TypeError: Cannot call method ‘getValue’ of undefined]. No data is sent to server.

The line causes it is

dhtmlx.js:34447 str+="&"+pref+"c"+i_c+"="+this.escape(c.getValue());

This is my code:

	var activityGrid = new dhtmlXGridObject('mygrid_activity_container');
	activityGrid.setImagePath("/dhtmlx/imgs/");
	activityGrid.setHeader("Type,Start Date,Start Time,Summary,Completed,");
	activityGrid.setInitWidths("50,75,75,400,75,75");
	activityGrid.setColAlign("left,left,center,center,left,center,center");
	activityGrid.setSkin("light");
	activityGrid.setColSorting(",,date,str,str,,");
	activityGrid.setColTypes('co,dhxCalendar,co,txt,ch');
	activityGrid.attachFooter(["Add an activity","#cspan", "#cspan","#cspan","#cspan",$('#activity_footer').html(),"#cspan"], ['text-align:right']);
	activityGrid.init();
	
	activityGrid.load('/activity/getActivities?person_id=' + person_id, 'json');
	activityGrid.setDateFormat("%Y-%m-%d");
	
	var dp_datasource = '/activity/someaction';
	var dp = new dataProcessor(dp_datasource);
	dp.setUpdateMode('cell');
	dp.enableDataNames(true);
	dp.init(activityGrid);

Unfortunately we cannot reproduce this issue locally.
make sure that you are having a latest version of dhtmlxdataprocessor. You can download the newest version from our site http://dhtmlx.com/docs/download.shtml