I had the same problem with my HP OfficeJet Pro L7590. Downgrading to 3.12.4 worked. I documented my steps for building the 3.12.4 debs here:
http://askubuntu.com/questions/153746/xsane-failed-to-open-device-hpaio-net-photosmart-c5100-serieszc-hp5180-err/178838#178838
I had the same problem with my HP OfficeJet Pro L7590. Downgrading to 3.12.4 worked. I documented my steps for building the 3.12.4 debs here:
http:// askubuntu. com/questions/ 153746/ xsane-failed- to-open- device- hpaio-net- photosmart- c5100-serieszc- hp5180- err/178838# 178838