It doesn't really qualify the discs, unfortunately. Memorex does not manufacture its own media, but rather it gets other manufacturers (usually crappy ones) to make discs for it and rebrands them. Which manufacturer supplies it with discs varies from time to time, so there is no way to tell what you are really getting each time you buy these discs, except that they are probably crappy.
LG's writers have never liked poor quality media much. For that reason, you can use crappy discs on another brand of writer and they may work, but they may not work with your LG writer. We don't recommend them anyway, since although they may work, they may not be able to last down the road.
kg's suggestion about using DVD Identifier is valid, since it will help us find out who made those discs and if they are supported by your writer. It is possible that the discs are not supported by the writer and that is why the writer will not recognise them. If DVD Identifier cannot return any sort of media code, we will then know that your writer does not support those discs.