When local variables are used to bind  into PL/SQL variables, 
ora_bind accept, but when ora_exec try to copy the results
into PHP variables, it fails.

exemple :
$c is a valid Oracle cursor;
test1 is Oracle function which

function test () {
global $c;
$z = 4;
ora_parse($c,"begin :z := 3; end;");
ora_bind($c,"z",":z",80,2);
ora_exec($c);
return $z;
}

echo test();

result :
4

}
echo "11.2 => y=".test2()."<br>\n";