Mac OS X 10.3.9
Some people are reporting problems with Java (which is used by RockGarden) after updating to Mac OS 10.3.9. this email describes a solution which is to update the pre-binding. You can do this using the command-line or any number of maintenance tools (eg. OnyX (free) or Cocktail (shareware)). Others, myself included, have not had any problems with the update. It seems to be hit-or-miss.
You can perform this procedure by opening Terminal (located in Applications/Utilities/) and typing this command, followed by the enter key:
sudo update_prebinding -root / -force