where is qvfb?

[jpn]

That's the package which i built : qt-x11-opensource-src-4.3.1.tar.gz

Shouldn't qvfb be built into the "bin" directory? All the components are ok except qvfb(designer , assistant...)

It's not built by default, because I guess most people don't need it. It's in tools/qvfb. It's clearly described in the document I already gave a link to.

Isn't qvfb part of Qtopia, not Qt?

Actually it's part of Qt.