Epic War Age (EWA) - Adapted Mod Collection

Yes, my video card has 128 MB of memory.

Is it possible to somehow optimize the mod EWA_VisualWorld.pak so that my video card can handle it?

I'm not an expert, but I don't think so. The pak file you're talking about likely contains high-resolution textures. They are loaded into the video memory. Unfortunately, if there isn't enough video memory, they can't be loaded, which causes the game to crash.