I must not have done it right. Here's what I changed in Quake3Map main.cpp (the "addMeshSceneNode" was already there, I just uncommented it out, and commented out addOctTreeSceneNode):
if (mesh)
{
//node = smgr->addOctTreeSceneNode(mesh->getMesh(0), 0, -1, 128);
node = smgr->addMeshSceneNode ...