Having the exact same issue on a fresh install of Ubuntu 6.06 Server using
zcs-4.5.5_GA_838.UBUNTU6.tgz.
The Finish/Next buttons are greyed out on the Create Account page. I am however, able to use the zmprov command to create and or modify accounts i.e.
./zmprov CreateAccount
mario@example.com good4now.
I didn't think that re-installation would help but tried it anyway with no avail.
Help?