I had the same problem! When I removed the hatch garage to fit a liferaft cradle to it, I found that there were two screws missing from the hatch sliders, and also it was broken in two places due to over tightening of the screws. The slider is too narrow, and has insufficient ‘meat’ either side of the screw holes. If you tighten the screws too much, the edge splits. Later models (even 2003 vintage) have s/s sliders, which of course do not fail. One solution would be to fit wider sliders, or replace the nylon ones with stainless.
Michael.