I am using 10.5.2 I had thought I'd read something about 64- vs 32- bit versions of the library but that might be getting confused with the linux issue.
I updated my solution documented on the above link to include details on how to download the file into the correct place via the terminal.
curl -o ~/Applications/arduino-0013/Arduino\ 13.app/Contents/Resources/Java/librxtxSerial.jnilib http://iharder.sourceforge.net/current/java/librxtxSerial.jnilib
I'd appreciate it if people could try that because documenting how to save it graphically into the correct place will take multiple steps--and I just wasted a stupid amount of time fighting with curl and spaces in file paths for reasons I don't understand. :-/
--Phil.