yup, you need to shelve the dodgy media for now. trust me i do 20 or so of these threads nearly every night. Crap media is one of the biggest causes of burning problems. Put it this way, we have nailed down everything as far as the logfiles show. Buy a pack of Verbatim datalifeplus for a few dollars and you can do 'Simulation' burns with the first disc out of the tub without actually writing to the disc. If you don't have a problem you're sorted; if you do have a problem your burner could be faulty. Either way all it's cost you is a tub of top notch media that you could get refunded, as my time here is free :)
..for the horrors of bad media see the 2nd link in my signature and see the hassle that crap & sup-par media causes, it keeps people like me busy/entertained for hours :)
they look ok BUT i'm in the UK so don't know if those are the cheapest you can get (for instance i only buy in tubs of 25 for £8 plus postage). Have a look thru these Verbatim threads as a few of us banter about media constantly, there should be some cheaper deals in there -
This is one of the reasons i push good media so much, all the tweaking of settings is necessary, but more often than not bad media will always bit you on the bum. happened to me, and cost me a lot of money, but it's in that link in my sig..