D64 textures in DB2 ?

hello all, i've been working pretty hard on doom builder for the last week, am totally hooked on it, and am wondering why when i load the doom64_abstin WAD file to my resource list, roughly 3/4 of the floor and wall textures are missing, limiting creativity quite a bit. i'm curious if theres a way to enable or find the missing textures... any one out there care to grace me with their vast knowledge?

Do you have the TC installed on your computer? Because it requires the Doom 2 wad from what i know.