Everytime it checks the Calibration, it also downloads the default USER_DATA15 file from their servers. So you need to let it do the Calibration before adding the USER_DATA15 file. The game only checks the Calibration the first time you start the game up from the Dashboard or every 2 or so hours of being online (but only if you exit after that amount of time).
I haven't figured out a bypass for that yet, other then replacing the file after the game Calibrates.
hmm.. what if you're playing offline? i don't have a gold account so would that perhaps make it not check every two hours or so?