FF13 has some missing dependencies as libpango1.0 and libxft2. Maybe the libs got removed from the system when I de-installed FF12 before?

Without libpango FF13 did start but nothing was visible.

The libs also couldn't be installed afterwards with "apt-get install -f" because the signature test failed. I had to use incept to install them from /var/cache/apt/archives. Now everything seems to work fine.

I would recommend to wait for the fixed version in in the Ovi store.

M.