I don't see any problems with the download itself, so my best guess is that you don't have the drivers for the webcam installed on your PC. Press Win + R on your keyboard, then type devmgmt.msc in the Run box that pops up and press Enter. Now, look for a category called Imaging devices and there you should see your webcam's name (HP Webcam -number-). Right-click it, then select Update Driver and have Windows search automatically for a new driver. Once the process is completed, try using the MediaSmart Webcam tool again.
If that doesn't do trick, you can download the universal webcam driver from the HP Support website and install it on your PC, but it's designed for Windows 7, so it may not work on other operating systems.