Hello, I faced a bug with default /etc/sane.d/dll.conf config. When trying to run any sane-based application, including ones in sane-backends (scanimage for instance) I get a segfault and 'fail to load parport, parport_pc, lp modules' messages. The answer was on google here -- http://www.linuxquestions.org/questions/debian-26/xsane-segmentation-fault-731788/ -- just commenting out the "smfp" from config above. Its only happens on non-root users.
Sorry, this must be a different problem. The link you posted relates to the "smfp" backend which is not part of sane-backends. Would be nice (if this is still a problem for you) if you would attach the actual output of "scanimage -L".
Please re-open if you can tell me a reason why this could be a sane-backends problem. Thank you!