bbText doen't work

heres the code

BBTexture u;
BBModel s;

s = bbCreateSprite();
u = bbCreateTexture(200,20);
bbSetBuffer(bbTextureBuffer(u));
bbCls();
bbText(1,1,"Loading",1,1);
bbSetBuffer(bbBackBuffer());

bbEntityTexture(s, u);

the string doesn't appear... Why?