divxz:
I'm certain that it won't make the conversion on your tiger, even after installing latest java, as the mencoder component in it is windows specific. Did the user interface work on your apple?

On the bright side, there exists a version of mencoder for osx as well. Alas, as I don't have a mac, I cannot easily make a version that would do the trick on an apple. I can try to have a look at it tomorrow.