LyX ⇒ lyx failed to generate pdf with bookmark

[hugo]

I'm using Lyx 2.02; my OS is Ubuntu 12.04.3 LTS kernel release Linux 3.2.0-53-lowlatency x86_64
The problem is when I generate a pdf file, there are not bookmarkS!. Document's Setting in PDF properties is:
GENERATE BOOKMARK YES
NUMBERED BOOKMARK YES
OPENED BOOKMARK YES
LEVEL 6

Anybody knows what is happening?