Ridata disks aren't the very best, but are generally far from the worst choice you can make. Do you know the mid code on these disks? You can use DVDIdentifier for that.
MysticEyes is right in that you can improve compatibility by bitsetting these +R disks, but we'd have to know the make and model burner you have before we can tell if it has this capability.
One thing that hasn't been mentioned yet is your burning speed. Sometimes you can slow down the burn a little and get better results. If you are using 16x media, I'd slow the burn down to 8x or 12x.