Ok, so I thought I'd let everyone know, to hopefully save them some trouble when burning DVD-R discs. So I decided to buy some Sony DVD-R's 1-8x compatible for my iMac Rev. B because I figured Sony were very compatible dvd-r's and would work fine. Long story short, they didn't work. The same error message kept coming up...and I even got online with Apple Chat and they said to reset the PRAM and NVRAM. Did that, and for the first disc afterwards the Sony DVD-R's worked. However, the second one I tried (third, fourth, fifth ect.) and I was back to the same error message. Got back online with Apple Chat, and I didn't want to believe them by them saying to try a different brand of DVD-R...especially since one already worked from the bunch...but I decided to give it a whirl. Lo and behold, the first disc I tried lying around the house (a Memorex DVD-R) right after I had tried a sony dvd-r worked like it was gold. So apparently, the brand of dvd-r drive in the computer makes all the difference. These sony dvd-r's work fine on the Powermac's at school (because of the sony dvd-r burner in the computer) but they sure don't get along with my iMac. Point of the story...don't buy Sony DVD-R's for an iMac rev. b computer, because you'll have a lot of trouble with them. They may work fine on other mac's but not this iMac and not this revision. End of my rant.