hplib + sane

["Bernd Prager" <bernd@prager.ws>]

I have an HP OfficeJet connected via HPLIP.
"scanimage --help" reports:
List of available devices:
    hpaio:/net/OfficeJet__K60?ip=192.168.2.11
but
"scanimage -d hpaio:/net/OfficeJet__K60?ip=192.168.2.11"
always returns with:
scanimage: sane_start: Device busy

/var.log/messages reports:
scanimage: warning HP-SCAN channel already closed: scan/sane/hpaio.c 518
and /var/log/syslog says:
hpiod: invalid scan response 1 socket 5 JetDirectChannel::Open: line 97
hpiod: invalid channel descriptor:-1

I run:
- hplip 0.9.3-3
- libsane 1.0.16-4
- sane 1.0.14-1
- kernel 2.6.14.3

Can anybody help me?
Thanks,
-- Bernd