Chrooting is probably what you're looking for.
It's probably just drm.You might want to add intel_agp or i915 or drm_kms_helper to MODULES in /etc/mkinitcpio.conf
Figured it was, wikipedia said it was IA32, so maybe we need to make it i686 so there's no question.
How are you starting xfce4?What's your .xinitrc look like?
If you have a broadfailure card, you will probably need broadcom-wl-pf-core2.
Does your user have access to the optical group?
Have you restarted nfsd?
You might use smartmontools to check to see that the drive(s) aren't failing.
In a normal case, you probably don't need /mnt and /mnt/data unless they are in fact two separate entities (/etc/exports).
This is a nfs4 unmount bug.