When I got my SSD installed in my MacBook, I swapped out the (defective) DVD for a caddy from Mac:Upgrades to house the original boot drive. This was completely unrecognised, but I didn’t have time to worry about it, so put the old boot disk in an external FW400 case and used the data from there. I assumed there must be something wrong with the ATA interface on my MacBook’s motherboard, which could explain the DVD not working.
Long story short, I popped open the MacBook and another almost identical one with working DVD and tried all the combinations of disks I could. The odd result of this is that the original boot disk was the only one that didn’t work in the caddy – every other drive I tried worked. Very odd. Anyway, I just put a different drive in the caddy and used its external case for my rebellious original boot disk. I can’t think of an explanation for that set of circumstances…