I see the issues on 12.04 it doesn't work 

you can install firebird and use as alternative inside a schroot 

http://www.binarytides.com/setup-chroot-ubuntu-debootstrap/

install 

sudo apt-get install software-properties-common python-software-properties

then continue with firebird 2.5 packages

https://help.ubuntu.com/community/Firebird2.5

apt-get install firebird2.5-classic in the chroot