so you have done an sbf back to 2.3.340 froyo.
and you rooted, and what are you trying to download from the market?
im not sure i follow your question, it seems strange, but i will do my best at helping you
-you have sbf'd before?
-make sure you download the CORRECT sbf file which is the full system, the 2nd link in my signature will help you with that
-once you boot to bootloader, make sure your battery is AT LEAST 40% cause sbfing will eat your battery alive
-once the phone reboots remove the battery and put it back in
-boot using the power+home, let go of power when you see the Moto M but continue holding home
-once you see the exclamation you hit the search button, then proceed to data wipe and cache wipe, then reboot?
-once its booted you root, and reboot?
-once your rooted, do you install Droid X or Droid 2 bootstrapper?
-do you hit bootstrap recovery? and then reboot recovery?
-do you wipe data and cache and dalvik cache before installing the 2 part rooted GB???