My wild guess would say that it could still be the same kind of problem, just at a lower level (e.g. library module that xine always uses instead of software file that you choose to have xine use). Possibly try this using the linux kernel that doesn't use the PAE memory address extensions and see if it works?
On another wild guess on my part, the following may be of assistance: https://bugs.launchpad.net/ubuntu/+s...ui/+bug/363880
I know the linux distribution there is Ubuntu and not Slackware, but it may help anyways.