In my case; I'm using ubuntu 10.04 64bits and I have an Epson Stylus SX218
So I installed:
1) epson-inkjet-printer-workforce-320-sx218_1.0.0-1lsb3.2_amd64.deb
2) iscan_data_1.6.0-0-all.deb
3) iscan_2.26.1-3.ltdl7_amd64.deb
4) sudo apt-get install lsb