Which macosx_setup.command did you run? I think you need to use the script from Processing (not the one from Arduino), as RXTX changed some things between the version in Arduino 0003 and the newer one in the latest versions of Processing.
I ran the one that came with Processing, as did Nick. The release I used was 0114.
The script goes for /var/lock/ (to be owned by group uucp) instead of /var/spool/uucp as in previous versions. /var/spool/uucp does not contain any left-over lock files on my machine.