here is the thing again,
$dateback1 = $monate[$dateback]. "nbsp;"; date('Y');
here $dateback is a object of DateTime type object.
now i can guess you are trying get the name of month from
monate
so what you need to do is get the month value from
$dateback. So find out the function that return month integer value.
$dateback1 = $monate[$the_month_value]. "nbsp;"; date('Y');
figure it out ;)