Well I manged to fix it after all. I put in my old CDR-RW and the new DVD-RW and set the jumper on the new one to slave.
Was I supposed to set the new ones jumper to slave even after having taken out the old one?

Seems odd, was the old drive jumpered as a slave?

Nope it was jumpered as the master.

I had to take my old drive out and left my new drive jumpered as slave and it still seems to be working fine.