Neither Xsane nor sane could find the Plustek scanner on the parallel port unless you were logged in as root. Not something you should.
It turns out that /dev/parport0 is missing. To fix that enter /sbin/modprobe ppdev somewhere towards the end of rc.parallel in /etc/rc.d. Make sure rc.parallel is executable so it runs at boot time. Also at boot time in rc.parallel has a couple of places where the script looks for /proc/ksyms. There is no /proc/ksyms. There is however a kallsyms so change the ksyms to kallsyms and the scripts will find what they're looking for.
That is all it took the get the scanner working as a regular user. Just for drill check to make sure the permissions on /dev/parport0 are set to 660.
I don't understand the problem with getting the /dev/parport0 link setup. I presume it is not needed usually.
Have a nice day.