Tree Structure Problem

Hi all,
Im trying to design a tree structure from code i got on a website. Its suppposibly coded for CS3 but im getting an error coming up. I know it has to be with the version but can anyone tell me what the correct word is instead of TreeNode for CS3. The error thats appearing is :
Description:1046: Type was not found or was not a compile-time constant: TreeNode.

Thanks a million for ye’re help always!
Mags