Chances are you’ve got some random subset of Project Threepio then, because it’s always included a README from version 1.0. How did you get it? I’d recommend downloading the full project (lots of info in first post, no direct link). I wouldn’t be surprised if you just got a bunch of SRT files (included with the movie?), and that would definitely cause needless confusion and problems. The very least of which is, without a README and version number, I have no idea if you’re using antique subtitle files with tons of problems or the latest ones.

That said, the same naming convention rules apply, so you probably want either ESB-eng-native or ESB-eng-sdh-native, depending on whether you want SDH or not. SUP format is preferred over SRT, although for English it should not make a huge difference.

EDIT: I just PM’d you. Yes, I know the project is large. That’s probably why you ended up with a small subset of it 😉