not sure on your cooker model but when you light a appliance that requires you to keep the control held in for a few seconds before releasing, you are doing so to allow the pilot flame to heat a thermocouple which once heated holds the gas valve open and allowing you to fire the main burner. these thermocouples can burn out and stop holding open the valve resulting in the flame extinguishing when you relese the control. best bet is ring a appliance service centre in your area and explain the problem along with the make and model. see if parts are available. i love gas/appliances but i tend to avoid repairing cookers.
ste
November 2009