Transferring music videos to ipod

so heres the dilemma. i purchased 2 music videos from itunes and tried sending them to the ipod. the vids wont transfer because it says the ipod doesn't recognize them?? am i missing something here? shouldnt it be a given that anything sold on itunes is compatible with the ipod? did i miss a step? helllllp....i dont wanna feel like i wasted 4 bucks on 2vids i cant use.

What iPod do you have? Have you updated the software for it recently? How many other videos do you have on it now?

the 80GB ipod..i have to update the software for it?....no other videos. i just bought it friday night