I've been searching this forum for an answer to my problem since yesterday, I have exactly the same issue like yours but on a Pioneer 112D (Stuck at 51% everytime), I had 2 packs of Infinity 360s first pack went through 100%, but second pack (bought from a different branch) had 100% fail rate, I thought my drive must be screwed. But after some research on google, I went out just before to buy a pack of Verbatim 2.4x it's gone pass 51% now and onto the second layer no probs
Looks like the suggestions are correct that a lucky batch of cheap DVDs may give you some winners but the sucess rate do vary from batch to batch.
Lesson learnt - Verbs only from now on
