After I edited core/libengine.py, It runs very well!!^^
I think that it was only problem on ubuntu 11.04.
thanks tuxplayer, and eyecreate!!^^
i change the author to you, can you now edit it?
The solution is twofold. One, you must use the mercurial version. Two, you must make this manual edit.
Line 3041 of core/libengine.py should read like this:
surf = pygame.transform.scale(surf,(int(size),int(size)))
Seems fine to me after those changes.