As mentioned in both previous posts, first you need to wind
the furling line onto the drum before you can roll the genoa onto the stay.
More importantly, you need to take a good look at the angle between the spinnaker
halyard and the forestay. If the angle is very small, there is a good chance that the halyard will wrap around the forestay when furling the genoa.
This can certainly lead to wrecking the forestay.
Take a look at this, will explain the wrap problem