Whenever a new update comes out it's always good to do a Flash cache memory clear.

As the game loads, right click inside the area of the game.
Slide the slider to 0.
Make sure the check box is NOT set.
Reload the game.
Be prepared for that first load to take a long time.
When it asks to allow Bushwhacker to save into your flash you have to allow it.
From then on it should be good again until your computer just can't hack it anymore.

There is another way to clear Flash but I forget how, some URL for it.

That's one other way, but Justin has shown another that does not require loading any foreign software, directly on the web site of the makers of Flash where you can control EVERY aspect of Flash in a graphical user interface web form.

That will work for you for a few months and then you will have to download another browser, and then again a few months after that...
YOUR Flash memory for that browser for that server/app is getting full or corrupted and can easily be fixed. There are a large supply of browsers out there but why give up on one?
P.S. I use the following 8 for various things, Firefox, Chrome, Opera, Safari, Sea Monkey, Comet Bird, and Iron. I do not use Internet Explorer even to line my bird cage...
All these browsers work well with Bushwhacker, even Firefox which was a dog for me a long time ago until I did what was outlined above.
All these browsers have features that I use for various things.

It would be better if DJArts fixed just how much computer resources this massive game takes. Nothing else I play uses anything near this. I can't imagine they get any new players for this game who have never been previously exposed to this game.
And it would be great if they and the makers of Flash figured out how to stop Flash memory leaks from any application that uses Flash.