Apparently I can't read. Sorry 'bout that. I've been up a while, insomnia. It's 11AM here and I've not yet slept.
Okay, do me a favour, just try one more time. Delete entirely rockbox.iriver and your .rockbox folder, and extract a fresh one. I'm thinking the most likely problem is not that you don't have the folder, but that it's somehow incomplete . So completely removing it before installing a bleeding edge build might help.
It sounds like you're copying over it, since you use the word "overwrite" so I'd like you to erase everything, and then hold Record while booting to clear the settings once more on a completely clean build.