[exsencon]

OK,since I am having the same problem,here are my answers to your questions:
1.Error
linux-f6nz:/home/zeger # rpm -ivh /home/zeger/Download/scangearmp-common-1.10-1.i386.rpm
error: Failed dependencies:
libusb is needed by scangearmp-common-1.10-1.i386

2.Output of scanimage _L

linux-f6nz:/home/zeger # scanimage -L

No scanners were identified. If you were expecting something different,
check that the scanner is plugged in, turned on and detected by the
sane-find-scanner tool (if appropriate). Please read the documentation
which came with this software (README, FAQ, manpages).

3.In yast I get as installed (installed them myself)

libusb-0_1-4
libusb-0_1-5
libusb-1_0-0
libusb-1_0-devel
libusb-compat-devel
libusbpp-0_1-4
libusbprog0

Not installed (conflicting with one of the above)
libusb-devel
For me it looks like I am missing the plain old usblib!I am running quite a lot of linux distros and they all installed the canonMP520 printer AND scanner when I provided the canon supplied drivers.Never asked me about usblib.
Any suggestions?
Thanks