1) While I was wipe wiping my feet with wudhu there was a very bit of dirt on my feet. Is my wudhu valid?

2) When wiping the feet does it have to be from the nails of the toes or can the wiping or can it be from the toes without touching the nails.

1) If it was across the foot, then it is void, while if it was a spot in a place, and you wiped the whole foot, then it is OK.

2) It has to be from the beginning of the nails