hi there after some help

my nearly 7 yr old son, who has always been really good at going to bed (ie never complains or stalls etc) has suddenly started saying he is having bad dreams at night so he doesn't want to go to bed, he never tells me in the morning just at night time before bed. i have tried everything telling him to dream of his favourite thing in the world to do etc etc, but he just says he can't.

any suggestions this is getting to be a bit hard as he is not getting to sleep until after 9pm which is okay on weekends but definately not during the school days.

thanks