Seeing as Aeria swept the other posts regarding lost data due to their uninstaller under the rug, I figured I'd have a go at this one more time. The basic deal is, if you chose to install to any other directory other than the one given to you in the installer, it will uninstall all the OTHER folders in that directory. The basic idea is, their installer installs to that directory exactly, not creating it's own subfolders, so when you click "uninstall", it takes everything in that folder and destroys it.
How does one fix this? Either you install it to the folders given to you, or we enter the worst case scenario: You actually used the uninstaller, now you have lost data. If you haven't gone on an install spree, you can actually GET THE DATA BACK.
Go there. Piriform's Recuva is a Freeware downloadable unerase wizard with an easy to use interface. It asks you where the files you want back are, and tells you if they can be recovered or not. I just used this myself, it works, so if you encountered any of this trouble, pick your jaw up off the ground and download it.