I'm using the TBS 6991 on ubuntu 12.04 64 bit machine, got the tbs drivers from their website. created a directory called TBS in my homedirectory and copied the follwing files into it:
linux-tbs-drivers.tar.bz2
v4l-cx23885-avcore-01.fw
then open up a terminal and do this:
tar xjvf linux-tbs-drivers.tar.bz2
cd linux-tbs-drivers
as I have a 64 bit machine I have to do this (differs on 32bit):
sudo ./v4l/tbs-x86_64.sh
sudo make
sudo make install
now your TBS6991 is installed, reboot your machine