I think your color is too dark. Try changing the values to (255,25,255,255) and check the result.
I created a sample project (in Beta 2), and only changed these lines:
.h:
class HelloWorld : public cocos2d::LayerColor
.cpp:
if( !LayerColor::initWithColor(Color4B(255,255,255,255)) )
The result is a white background.