For SANE, the first thing you need to do is run
as root. That will tell you where sane thinks the scanner is. You can then find the scanner location in /dev and change the permissions so you as user (or the scanner group) is permitted to read-write-execute the device.
Then you can try running xsane as user.
As Root ran "sane-find-scanner," and the response was:
Product=0x4d11 [PSC 1400 Series] at libusb:1;3
# usb scanner (probably) detected. It may not be suported by Sane.
Try Scanimage -L and read the backends manpage.
"Scanimage -L" was run with the result: No scanners were identified.
I took this information, and using the command "ls -la" at terminal discovered these current permissions:
wxrw-r--r-- 1 root root 32726 2007-02-15 22:43 libusb.a
-rwxr-xr-x 1 root root 789 2007-02-15 22:43 libusb.la*
lrwxrwxrwx 1 root root 19 2008-02-12 17:38 libusb.so -> libusb-0.1.so.4.4.4*
Are these the same permissions your system show?
BTW ran xsane and no scanner found.....