So what, you're using a nexus of n.i.n.e.-h.u.n.d.r.e.d. m.e.g.s. ? O_O O_O O_O

In that case, I'm afraid, it is indeed _very_ likely for A6 not to be able to handle this. But since you usually have to push up your nexus when creating hundreds of entities in WED, why not try creating some of them at runtime via ent_create instead? Maybe this method is able to overgo the nexus limit. Just a guess, though.

I'd honestly recommend reducing your levels memory usage whereever possible. A nexus of 900 mb is almost impossible for may computers to deal with, I assume.