[sane-devel] losing hair and sleep over this

[noah]

scanners don't work on my system!!!
i've tried three scanners. two of which were admittedly unsupported, but the third of which is supposedly fully supported by sane.
they were all usb.
this last one is an epson perfection 640u. here's what happens:
i plug in the scanner.
quoth /var/log/messages:
Oct 28 22:36:49 cobaltdhcpb60 /sbin/hotplug: arguments (usb) env (DEVFS=/proc/bus/usb OLDPWD=/ PATH=/bin:/sbin:/usr/sbin:/usr/bin ACTION=remove PWD=/etc/hotplug SHLVL=1 HOME=/ DEVICE=/proc/bus/usb/002/006 PRODUCT=4b8/10c/1 TYPE=255/0/255 DEBUG=kernel _=/bin/env)
Oct 28 22:36:49 cobaltdhcpb60 /sbin/hotplug: invoke /etc/hotplug/usb.agent ()
Oct 28 22:36:53 cobaltdhcpb60 kernel: hub.c: new USB device 00:14.3-1.2, assigned address 7
Oct 28 22:36:57 cobaltdhcpb60 kernel: message.c: usb_control/bulk_msg: timeout
Oct 28 22:36:58 cobaltdhcpb60 kernel: message.c: error getting string descriptor 0 (error=-110)
Oct 28 22:36:58 cobaltdhcpb60 kernel: Manufacturer: EPSON
Oct 28 22:36:58 cobaltdhcpb60 kernel: scanner.c: probe_scanner: User specified USB scanner -- Vendor:Product - 4b8:10c
Oct 28 22:36:58 cobaltdhcpb60 /sbin/hotplug: arguments (usb) env (DEVFS=/proc/bus/usb OLDPWD=/ PATH=/bin:/sbin:/usr/sbin:/usr/bin ACTION=add PWD=/etc/hotplug SHLVL=1 HOME=/ DEVICE=/proc/bus/usb/002/007 PRODUCT=4b8/10c/1 TYPE=255/0/255 DEBUG=kernel _=/bin/env)
Oct 28 22:36:58 cobaltdhcpb60 /sbin/hotplug: invoke /etc/hotplug/usb.agent ()
Oct 28 22:37:01 cobaltdhcpb60 /etc/hotplug/usb.agent: Setup scanner for USB product 4b8/10c/1

(was that too much?)
sane-find-scanner replied with:
searching for USB scanners:
checking /dev/usb/scanner... failed to open (Invalid argument)
checking /dev/usb/scanner0... failed to open (Invalid argument)
checking /dev/usb/scanner1... failed to open (Invalid argument)
checking /dev/usb/scanner2... failed to open (Invalid argument)
checking /dev/usb/scanner3... failed to open (Invalid argument)
checking /dev/usb/scanner4... failed to open (Invalid argument)
checking /dev/usb/scanner5... failed to open (Invalid argument)
checking /dev/usb/scanner5... failed to open (Invalid argument)
checking /dev/usb/scanner7... failed to open (Invalid argument)
checking /dev/usb/scanner8... failed to open (Invalid argument)
checking /dev/usb/scanner9... failed to open (Invalid argument)
checking /dev/usb/scanner10... failed to open (Invalid argument)
checking /dev/usb/scanner11... failed to open (Invalid argument)
checking /dev/usb/scanner12... failed to open (Invalid argument)
checking /dev/usb/scanner13... failed to open (Invalid argument)
checking /dev/usb/scanner14... failed to open (Invalid argument)
checking /dev/usb/scanner15... failed to open (Invalid argument)
checking /dev/usbscanner... failed to open (Invalid argument)
checking /dev/usbscanner0... failed to open (Invalid argument)
checking /dev/usbscanner1... failed to open (Invalid argument)
checking /dev/usbscanner2... failed to open (Invalid argument)
checking /dev/usbscanner3... failed to open (Invalid argument)
checking /dev/usbscanner4... failed to open (Invalid argument)
checking /dev/usbscanner5... failed to open (Invalid argument)
checking /dev/usbscanner6... failed to open (Invalid argument)
checking /dev/usbscanner7... failed to open (Invalid argument)
checking /dev/usbscanner8... failed to open (Invalid argument)
checking /dev/usbscanner9... failed to open (Invalid argument)
checking /dev/usbscanner10... failed to open (Invalid argument)
checking /dev/usbscanner11... failed to open (Invalid argument)
checking /dev/usbscanner12... failed to open (Invalid argument)
checking /dev/usbscanner13... failed to open (Invalid argument)
checking /dev/usbscanner14... failed to open (Invalid argument)
checking /dev/usbscanner15... failed to open (Invalid argument)
  # No USB scanners found. If you expected something different, make sure that
  # you have loaded a driver for your USB host controller and have installed a
  # kernel scanner module.

to which lsmod had this to say:
Module                  Size  Used by    Not tainted
lp                      8128   0  (autoclean)
8139too                19092   1
mii                     2188   0  [8139too]
crc32                   1764   1  [8139too]
ide-scsi                9936   0
ide-cd                 33896   0
scanner                11632   0

so, if anyone has any advice, that'd be great.
if this email is too much, please tell me, and i can abbreviate the problem.

thanks a lot,
noah