DVD-R help!

Hello, I have a NEC DVD+RW ND-1100A. Burning DVD+RW works fine but when I try to burn a DVD-R disk it does not work. Please tell me its possible because I bought a bunch of disks. I beilive it says that it is compatible with almost everything including DVD-R so i dont know why it doesnt work. Help would be appreciated. Thanks.

you might be able to crossflash to a 1300, I did, tricky and dangerous

Wait i just noticed, i think it only support 4x speed while the DVD-R im using is 8x does that matter or should it work anyway?