Description:
------------
I see:
  string set_error_handler ( callback error_handler)

Must be:
  callback set_error_handler ( callback error_handler)

Because:
"Returns the _previously defined error handler_ (if any), or FALSE on error." 

Reproduce code:
---------------
<?
class a
{
	function h()
	{
		echo "a::h()";
	}
};

set_error_handler(array('a','h'));
print_r(set_error_handler(array('a','h')));

?>