Sounds like you have a perfect need for DVD-RAM. DVDRW is in itself pretty unreliable, and when you ad packet writing the problems compound.
Your best option (costs aside) is the LG 4163B and a few RAM discs with InCD 4.
Upgrading your 1213 to a 1633/53 might have an effect, or might not. The odds are against it helping. In any case, I sure hope you have backups of your images apart from storing them on DVDRW discs. RAM is far more reliable, but still not perfect.
If you want to stay with the DVDRW, suggest you stick with multisession writing in Nero. Just put the photos in folders with dated names, and add new dated folders to each session, being sure to import the previous sessions to each new session. Then you will have a nice "time machine" disc with all previous versions of the files included. You can't delete stuff this way, but it's a lot more reliable.