Don't take this the wrong way, but there's an awful lot of newbs trying stuff half-cocked over on XDA (and here), messing around with things they don't understand.
To make matters worse, there's no big support base yet like there is with HTC or Motorola devices, and Samsung's method of doing things is alien to a lot of the devs on XDA.
And to make matters even worse, they're doing this crap, then taking the dead phones back to AT&T and acting dumb. THAT, my friends, is why bootloaders are locked.
So, STOP IT. Unless you're very comfortable with Android, have a basic understanding of Linux, and are willing to man up and eat the cost of the phone you're digitally beating on a rock so the evil spirits come out of it, STOP MESSING AROUND WITH SYSTEM FILES.
Bide your time, the phone is only 4 days on the market, and there will be how-to guides, tools, and a wealth of things to do to make your Captivate better.
