To be honest with you, if you're going to burn to Dual Layer discs I really wouldn't waste your time on anything other than Verbatim DVD+R DL's...... I only use the non Indian produced ones and have never had any problems with them, with the other media ID's (yours are RITEK-S04-66) you see very mixed results.
As Cynthia said above, I would also grab the latest copy of ImgBurn and then follow her excellent guide that will help you get to grips with burning