Hey! A GeForce 6150 LE, that's what I have. It's a bit of a difficult card, and does not work with the Nouveau drivers that AVLinux tries to use by default.
You'll want to install the NVidia drivers. You'll also need to delete a config file that causes problems with this card. Check the AVLinux manual for any questions you may have about these steps:
1. You'll need to boot into failsafe mode to get to the desktop on the live system.
2. Install AVLinux as normal.
3. Reboot into proprietary video driver maintenance mode. At the login, enter 'root' and your root password. Let the sgfxi script do its thing.
4. After the NVidia driver is finished building, sgfxi will ask you if you want to start the desktop. Select no.
5. Delete /etc/modprobe.d/nvidia.conf (it will cause crashes with this card).
6. Then, start the desktop:
service slim start
That should be all you need.