If you are using Java 7 on a 64-bit computer make sure you install both the 32-bit version and the 64-bit version. You need to have both as many Java programs will only work with the 32-bit version. They don't install into the same directory.
32-bit version installer, Version 7 Update 5
64-bit installer, Version 7 Update 5
If you have multiple old versions of Java installed it is a good idea to
remove them.
Good luck.
PS: The DrumUI Updater uses the exact same Java technology. I believe the same guy did both of the updaters.