Unable to update minecraft: Fatal error occured (4): null

Started it up, coming from the 1.4.1 pre-release I think, but it never gets past the launcher anyway:

$ ./minecraft
java.lang.NullPointerException
at net.minecraft.GameUpdater.downloadJars(GameUpdater.java:520)
at net.minecraft.GameUpdater.run(GameUpdater.java:286)
at net.minecraft.Launcher$1.run(Launcher.java:84)
Fatal error occured (4): null
java.lang.NullPointerException
at net.minecraft.GameUpdater.downloadJars(GameUpdater.java:520)
at net.minecraft.GameUpdater.run(GameUpdater.java:286)
at net.minecraft.Launcher$1.run(Launcher.java:84)