Unexpected Token (DRUPAL 7.26 - dhtmlx spreadsheet 2.0?)

ajax: function(url, params, callback) {
params = this.serialize(params);
dhtmlxAjax.post(url, params, function(response) {
if (response.xmlDoc.responseText !== ‘’)
callback(eval(’(’ + response.xmlDoc.responseText + ‘)’));
->> UNCAUGHT SYNTAX ERROR: UNEXPECTED TOKEN <
});
},

serialize: function(params, parent) {
	var parent_start = (!parent) ? '' : parent + '[';
	var parent_end = (!parent) ? '' : ']';
	var text = [];
	for (var i in params) {
		if (typeof(params[i]) == 'function') continue;
		if (typeof(params[i]) == 'object')
			text.push(this.serialize(params[i], (!parent)? i : parent + '[' + i + ']'));
		else
			text.push(parent_start + i + parent_end + "=" + encodeURIComponent(params[i]));
	}
	return text.join('&');
},