take it apart an clean off the rollers (some build up crud over time, not related to your immediate problem, probably).
then clean them out (This will help or fix the issue).
Then apply some sort of plastics lubricant to any moving parts. Use a paintbrush and less is better, like "This cant possibly be enough" sort of less.
Unless its in warranty and your scared to void it.
If you keep using it, whatever is causing the scratching/squeaking is going to increase the rate of wear and shorten the life of the accessory.
