This disc will play in your PC?!? Are all your scans like this? Do all your discs that scan like this play fine? If the disc plays fine with no freezing or pixelations, then I would guess that your burner is not a good scanner('understatement of the year' nominee). You could also try to scan in nero cd/dvd speed (go >nero/nerotoolkit/cd-dvdspeed/Extra/Disc Quality Test) to 'compare' results. I don't know if I can give other advice at this time concerning improving burn quality as we aren't sure WHAT burn quality you are getting. These discs should give excellent results at 4x burn speed. I would wait until we can figure out HOW to test before trying different media, although if you have some lying around, you could try a burn and scan to compare. It is important to have a good power supply, however if you are having power supply problems, I doubt bad scans on good discs would be a result, bad burns and/or bad rips...maybe, bad scans on good discs...doubtful.
edit-oops...posted before seeing bichonn's reply...give his idea a go first, although I can usually do stuff while scanning.