how can i fix my AEG Competence oven?

The oven shuts down after only 20 minutes or so in operation, it definately isnt the timer being incorrectly set !
on looking inside the top inspection panel two sets of wires (two white and two blue) leading into two small seperarate white rectangular components appear heat damaged and charred, i have attempted to re solder the white wires but upon turning on the oven within seconds the wire heats up and the solder joint breaks, any ideas ?

lenny
January 2009