@OP - When you say that it's "not working", do you mean that (a) the rotate button is grayed out in Bridge and/or the shortcut key doesn't do anything visible in Bridge, ... OR ... (b) do you mean that when you open the presumably rotated file in another application, it isn't rotated.
If the answer is (a) there are a few reasons this could be happening. For example, MrTom's comment on file types is probably correct (I didn't remember this limitation and didn't check it, but it sounds reasonable). You may also have a problem with your cache in Bridge. To test this, go to "Tools / Cache / Rebuild cache" in the Bridge drop down menus.
However, the more usual complaint is (b), not (a). If this is what you are experiencing, you have to realize that when you click the rotate button in Bridge, it does absolutely nothing to the data in the file. Instead, all it does is changes one bit in the metadata, the "orientation" tag. This is the same tag that is used by cameras so that no matter whether you hold the camera in landscape or portrait orientation, the photo will be displayed right-side-up when viewed using software that makes use of the "orientation" metadata tag. Some software does, some doesn't.
Let us know which problem you have.
Tom M