New to this myself but I think clear cashe is ok but clear data resets Xbmc to first run state and you might need to run wizard again from program. As for film freeze and buffering I had this and watched a video on YouTube about maintenance tweaks and 0 cashe.xml which made the movie continue to cashe to memory if you pause for a few minutes so download was always ahead of what your watching. Check out YouTube videos they have been a great help to me. Hope this is some help.