Problems with Realm Crafter Mega Terrain Module

I reciently purchased Realm Crafter for my son Will after he completed his 3D Game Design Camp which used the same software. I then purchased the MegaTerrain Module for the system, but are finding that it has a strange bug. The land area is tiny. Checking the Realm Crafter boards I have found that this may be related to the video card, but this is a very new computer with a new video card. If anyone has any information that might help, please post a comment.