Board is hanging running for long duration

Hi,
 
   I am working on at91rm9200 board.Ecos application is running fine but after running for more than 1 day board is hanging.I could see in hyperterminal it is coming to the hal_arch_default_isr( )  function with the interrupt number 1 after the board got hanged.Ethernet interrupt and IRQ0 interupt and two alaram timers  one with one sec and the other with 8 sec intervals are being used in the application.Could the cause of this can be spurious interrupt or can any one suggest me what could be the cause for such behaviour?

Thanks,
Neeraja.