Well, you have to use it at your own risk, because even though many people have patched their Vista UXtheme without any trouble, there are a few complaints that replacing the original UXtheme.dll creates problems.
But overall its safe. To ensure maximum safety,
always back up the files you are going to replace. And if you are still not sure if you would do it right, give
VistaGlazz a try, it's an automated patcher that takes care of replacing and patching for you
