Getting your T91 touchscreen in Ubuntu 9.10 Karmic Koala requires the following steps.
When i did this i configured the graphics card first and the the resolution to 1024x600. I'm not sure if this is a required step but i'd recommend doing it. To find out how you can see my blog post here.
First you need to install the evtouch drivers, open a terminal and type the following
sudo apt-get install xserver-xorg-input-evtouch
then reboot, after that the touchscreen will be working but most likely not correctly calibrated. There is an issue with the evtouch screen calibration in 9.10 so you need to run the calibration with no X server running.
The first command will stop X and take you to a terminal so either remember the steps after it or have another computer handy. Open a terminal and type:
sudo /etc/init.d/gdm stop
after this you will be asked to log in.
now run the calibration utility.
There were no instructions when i ran the calibration tool so here is what you need to do.
once it opens run your stylus around the edge of the screen then hit enter.
The top left cross will then go red, press the center of it and then release, the next cross should then go red. Do this for all 9 crosses and the configuration utility will exit when you click the last one.
next restart X by running
Note, if i didn't restart X and just rebooted from the command line the new configuration was not saved, not sure why.
hope this helps, good luck!