which lights are flashing.
if you number them with 1 on the left or at top and let me know.
Is that lights 1 2 3 and 4 or just 1 and 4
its just to make sure we get the right error code.
Ok thanks for that lights 123 and 4 indecate an f15 fault which is a heater relay fault
All you can do is remove the rear panel and on the left side is the main control board remove this remove 1wireing block at a time and refit it to clean the connections then remove the lid and make sure there is no loose connections on the dryer element then retry if still doing the same then the control board will need to be changed as the heater relay is built into the pcb. you can try these as they sell refurbished boards which come programmed for your machine.
If you need anymore info just get back to me
If the connections are ok then it looks like the main pcb.
What you might be best is getting hotpoint in on there fixed price repaire as they will need to programme the new pcb anyway you will need to ring them for the prices but you will probley find its about the same price as buying a new pcb itself.
Good luck with it.