using jquery ajax POST method returning 500 error

[warroyo90]

hi i am trying to use this code but keep receiving a 500 internal server error when this runs. is this an issue in my script or do i need to use it differently for zen cart?

jQuery.ajax({
   type: "POST",
   url: "/includes/templates/theme376/phpScripts/check.php",
   data: 'partNum='+ partNum,
   cache: false,
   success: function(response){
if(response == 1){
	$('#partNum').css('border', '3px #C33 solid');	
	$('#tick').hide();
	$('#cross').fadeIn();
	}else{
	$('#partNum').css('border', '3px #090 solid');
	$('#cross').hide();
	$('#tick').fadeIn();
	     }

}
});