I have a MEMOREX DVD+/-DLRWL1 F16 burner with Nero 7 and cannot get my Sony DVD-R's (version 2.1) to burn. I have the latest firmware available for the drive. I had the same problem with version 6.6 of Nero as well. If you seem to have this problem as i did, and others have then the solution is just this, either buy a different brand og rewriter or buy only memorex cd/dvd's that is just about all it will except. I bought me a LG Super Multi Rewriter to take its place from mwave and it has paid for itself by not waisting my dvd's............well worth the money to change.
I doubt your Memorex burner will only work with memorex discs. Burner brand and disc brand are not the only 2 variables taken in consideration to achieve a successful burn. Did you try using a different burning software? Change the burn speed? Any other software on your PC that might conflict with Nero? Multi-tasking?(some burners will buffer better than others). Cables?