I assume a usb scanner. Try unplugging the scanner while you are logged in as a normal user, then plug it back in again.
I think there is a right problem somewhere but my scanner works fine in
root but i can't use it as a user. Someone can help me ?
Before the scanner was unplugged. ]$ sane-find-scanner
# No SCSI scanners found. If you expected something different, make sure that
# you have loaded a SCSI driver for your SCSI adapter.
found USB scanner (vendor=0x05d8, product=0x4002, chip=GT-6801?) at libusb:002:002
