It's something in my environment. I installed sun's jdk and still, doesn't run. It gives me pretty much the same error:
alan@alan-desktop:~/Downloads/Pkg/Jinput/dist$ sudo /usr/lib/jvm/java-6-sun/jre/bin/java -Djava.library.path=. -cp jinput.jar:jinput-test.jar net.java.games.input.test.ControllerTextTest
Controller Env = net.java.games.input.DefaultControllerEnvironment@7ca83b8a
Dec 24, 2010 12:45:23 PM net.java.games.input.DefaultControllerEnvironment getControllers
INFO: Loading: net.java.games.input.LinuxEnvironmentPlugin
java.lang.ClassCastException: net.java.games.input.LinuxMouse cannot be cast to net.java.games.input.LinuxAbstractController
at net.java.games.input.LinuxEnvironmentPlugin.enumerateControllers(LinuxEnvironmentPlugin.java:256)
at net.java.games.input.LinuxEnvironmentPlugin.<init>(LinuxEnvironmentPlugin.java:112)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at java.lang.Class.newInstance0(Class.java:355)
at java.lang.Class.newInstance(Class.java:308)
at net.java.games.input.DefaultControllerEnvironment.getControllers(DefaultControllerEnvironment.java:160)
at net.java.games.input.test.ControllerTextTest.<init>(ControllerTextTest.java:54)
at net.java.games.input.test.ControllerTextTest.main(ControllerTextTest.java:86)
alan@alan-desktop:~/Downloads/Pkg/Jinput/dist$ sudo /usr/lib/jvm/java-6-sun/jre/bin/java -Djava.library.path=. -cp jinput.jar:jinput-test.jar net.java.games.input.test.ControllerReadTest
Dec 24, 2010 12:47:35 PM net.java.games.input.DefaultControllerEnvironment getControllers
INFO: Loading: net.java.games.input.LinuxEnvironmentPlugin
java.lang.ClassCastException: net.java.games.input.LinuxMouse cannot be cast to net.java.games.input.LinuxAbstractController
at net.java.games.input.LinuxEnvironmentPlugin.enumerateControllers(LinuxEnvironmentPlugin.java:256)
at net.java.games.input.LinuxEnvironmentPlugin.<init>(LinuxEnvironmentPlugin.java:112)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at java.lang.Class.newInstance0(Class.java:355)
at java.lang.Class.newInstance(Class.java:308)
at net.java.games.input.DefaultControllerEnvironment.getControllers(DefaultControllerEnvironment.java:160)
at net.java.games.input.test.ControllerReadTest.<init>(ControllerReadTest.java:252)
at net.java.games.input.test.ControllerReadTest.main(ControllerReadTest.java:301)
I don't have a clue of what it might be though

Is there something else I should check? BTW, I looked for jinput and it is in the repositories but only for 10.10, I'm using 10.04