Conbectivity between splitAt() and tree grid

I am constructing a tree grid.
In case I don’t specify a definite column for splitAt( ), it breaks and no grid is displayed.
But if the splitAt(1) is used, then the page loads properly.

When I checked the dhtmlx.js, I see that it breaks at

if (this.isTreeGrid())
return this._process_tree_xml(a);
			for (var i = 0; i < e.length; i++)
				if (!this.rowsBuffer[i + f]) {
					var j = e[i].getAttribute("id") || i + f + 1;
					this.rowsBuffer[i + f] = {
						idd : j,
						data : e[i],
						_parser : this._process_xml_row,
						_locator : this._get_xml_data
					this.rowsAr[j] = e[i]

The first column in my grid is a tree cell. But this.isTreeGrid() returns false, when splitAt(0) is given and the control goes into the for-loop and breaks my page. Please help me resolve this issue ASAP.
Your help would be highly appreciated.

To add to the issue:

Please note that I do not want to use, splitAt( ) functionality at all.
But I am forced to, otherwise my grid is not loading at all.

in splitAt() method you define the column that will start the unfrozen part of the grid.
Unfortunately it’s not available to use this method without attributes or with the values of the first/last columns.