The line with the absolute address was meant to be:
/home/chris/xorriso/xorriso-1.5.3/xorriso/xorriso -outdev /dev/sr0 -toc
The line with the absolute address was meant to be:
/home/ chris/xorriso/ xorriso- 1.5.3/xorriso/ xorriso -outdev /dev/sr0 -toc