Tvheadend

I have Ubuntu 14.04.1 LTS (3.13.0-45-generic) and Tvheadend 3.4.28~geb79aee~trusty as backend.
I installed the drivers 'linux-tbs-drivers_150130.tar.bz2' according to the documentation for my TBS6908 card.
Installation went OK.
Appreciate all help I can get ...

dmesg | grep -i TBS
[ 8.432304] TBS PCIE Detected TBS6908 Board Rev 3
[ 8.433476] DVB: registering new adapter (TBS PCIE DVB Adapter)
[ 8.595044] tbs6908fe: module license 'TurboSight Proprietary: http://www.tbsdtv.com' taints kernel.
[ 8.595178] TurboSight TBS 6908 Frontend Attaching...
[ 9.595734] TurboSight TBS6908 DVB-S2 card adapter0 MAC=00:22:ab:69:08:01
[ 9.595736] DVB: registering adapter 0 frontend 0 (TurboSight TBS 6908 DVBS/S2 frontend)...
[ 9.595773] DVB: registering new adapter (TBS PCIE DVB Adapter)
[ 9.595908] TurboSight TBS 6908 Frontend Attaching...
[ 9.598504] TurboSight TBS6908 DVB-S2 card adapter1 MAC=00:22:ab:69:08:02
[ 9.598505] DVB: registering adapter 1 frontend 0 (TurboSight TBS 6908 DVBS/S2 frontend)...
[ 9.598526] DVB: registering new adapter (TBS PCIE DVB Adapter)
[ 9.757506] TurboSight TBS 6908 Frontend Attaching...
[ 10.768223] TurboSight TBS6908 DVB-S2 card adapter2 MAC=00:22:ab:69:08:03
[ 10.768226] DVB: registering adapter 2 frontend 0 (TurboSight TBS 6908 DVBS/S2 frontend)...
[ 10.768331] DVB: registering new adapter (TBS PCIE DVB Adapter)
[ 10.768484] TurboSight TBS 6908 Frontend Attaching...
[ 10.771173] TurboSight TBS6908 DVB-S2 card adapter3 MAC=00:22:ab:69:08:04
[ 10.771175] DVB: registering adapter 3 frontend 0 (TurboSight TBS 6908 DVBS/S2 frontend)...

But still I can't scan ... which I did without problems with my cheap testing tuner card Hauppauge 5500 before.
What is the problem ?

sudo w_scan -fs -c SE -s s0w8 -C UTF-8 -O 0 -R 0
...
trying 'S2 f = 10747 kHz H SR = 25000 3/4 0,35 8PSK'
(time: 00:11)
trying 'S2 f = 10747 kHz V SR = 25000 3/4 0,35 8PSK
...
ERROR: Sorry - i couldn't get any working frequency/transponder
Nothing to scan!!