Very odd as this file should be included in the latest patch, but if it is indeed missing, please try and download the following file:
https://we.tl/t-LI5SvojZBz
Then place it in the following folder on your end, e.g. the folder that matches your World at War installation path:
C:\Program Files (x86)\Matrix Games\Strategic Command WWII - World at War\Pbem\DAT\v1.11.01