The following script generates a parse error on line 8 (Parse error: parse error, expecting `')'' in /home/dbellizzi/cvs/crm/htdocs/test.php on line 8

<?php
class Foo {
        function blah(){
                return "abcd";
        }
}
$foo = new Foo();
if (empty($foo->blah())){
        echo("foo->blah is empty");
}
?>

However, when changed to this script that assigns the variable before checking it with empty(), it works fine:
<?php
class Foo {
        function blah(){
                return "blah";
        }
}
$foo = new Foo();
$blah = $foo->blah();
if (empty($blah)){
        echo("foo->blah is empty");
}
?>

I have duplicated this on a few different machines, but if you need information on my setup, libraries, etc. please email me and I'd be happy to provide more information