Quote Originally Posted by Simetrical
When I clicked the shortcut, RTW started up, went through the initial loading screen, and then returned me to the desktop almost immediately. The data\sprites folder doesn't even exist. I must be doing something wrong—but what? Jerome, [cF]Adherbal? Any ideas?
Are you sure the original Rome dataset is still completely intact? The fact that it returns almost immediately could indicate that it's not even getting to the sprite generator execution.

Also, you need to make sure there are no -mod options on the command line, and since it's a modded game, there's a risk that some of the typenames have been renamed or removed from descr_model_battle.txt or descr_mount.txt ... i'd suggest you make sure that the typenames are there, the cas models reference valid textures, and so on. And of course run with -show_err on the command line as well.