Which OSX version are you running?
I can't see any numbers in the video. It's very blurred.
If Java 1.6 is not an option, then your are not running Leopard 10.5 & will be unable to use LW 5, as stated above.
If you read the LW 5 minimum requirements, you would have seen java 1.6 is a minimum requirement, thus so is OSX 10.5 since it's the only OSX with java 1.6.