TRusselo, Consider simplfing the process you outlined above...
Heimdall One-Click can be used for a much quicker one-shot method. There's a list of applicable packages here:
http://teamkomin.com/index.php?dir=Captivate/
You could use the Gingerbread bootloaders package and the TalonDEV package to upgrade bootloaders and get the latest CWM on the device in the easiest maner possible, also this will work on ALL platforms and not just Windows.
Put device in download mode
Click the flash button and hold the Volume + and volume - buttons until the device restarts
Click the Flash bootloaders checkbox
Click the flash button
the device should restart into recovery mode, if not, place the device in recovery mode
Select your ROM
You'll just need a Heimdall one-click made. Would you like one? I can remix those two packages into one and make the one-cick I described above.