Hi rkix,
Try clearing your flash and browser caches. Game and course files are stored in your cache and sometimes those files can become corrupt or outdated. Clearing your caches clears out all your old files and allows your PC to download the newest files from the server.
Please note that clearing your caches will reset all of your in-game options, so if you have any preferences for settings like graphical quality, flagstick animations or reflections you'll want to set those one more time before you tee off again.