Memorex CD-RW non-rewriteable?



Am I asking too much of a CD-RW, if I record a SVCD with an .avi file, watch it, then later erase it, and record, and watch another file with same disc??
Each time after the first, produces a very low quality, pixel-filled, terrible sound experience.

My Question: Is it just my choice of CDs?
Are CD-RWs not designed to be used as such?

My equip:
Memorex 700mb CD-RW 16x-24x
Nero Vision Expr. 3
Burner: Philips DVDR160P