If your scanner is similar to the 1200CU, here's how I got it going on Fedora Core 2...
From xsane: Failed to open device: 'gt68xx:libusb:002:006': Invalid argument
First up - I tried to download driver ftp://ftp.mustek.com.tw/pub/driver/B...LV10/panel.tgz
from the page http://www.mustek.com.tw/Download/dr...e/b1200cu.html
This expanded into a buggy (I shortcutted the whole readme after all) panel application. I was really only interested in the drivers themselves.
There was also .tar called "drivers" - this uncompressed into the essential files! Installing simply put them into the wrong place as follows...
[lancer@localhost lancer]$ scanimage
[gt68xx] Couldn't open firmware file (neither `/usr/share/sane/gt68xx/PS1fw.usb' nor `/usr/share/sane/gt68xx/ps1fw.usb'): No such file or directory
scanimage: open of device gt68xx:libusb:002:006 failed: Invalid argument
Alright - after the previous steps, the README told me to expect that files would be in /usr/local/bin/ This was correct. However, the error report from running scanimage (above) led me to believe the problem was simply relocating the files. so, (as root)...
[root@localhost root]# mkdir /usr/share/sane/gt68xx
[root@localhost root]# cp /usr/local/bin/ps1fw.usb /usr/share/sane/gt68xx/
[root@localhost root]# cp /usr/local/bin/ps1 /usr/share/sane/gt68xx/
From there - I fired up gimp and ran File > Acquire > Xsane... and presto! It was working.