WP 3.2: Assigning the return value of new by reference is deprecated

Assigning the return value of new by reference is deprecated

I have a full handful of clients returning this error after upgrading. The error *usually* comes up with references to wp-settings.php, but occasionally seems to reference other files. Checking the referenced lines in question, kludging them doesn’t seem to fix the error; it just returns a different line number, throws a WSOD, or another PHP error (usually the headers already sent error).

I’ve just rolled them back to WP 3.1.4 as a stopgap, but any helpful suggestions for troubleshooting this problem would be appreciated.