very true observation by juiceme.
The "easiest" way is to get a live distribution of some linux - you can use unetbootin to create a bootable USB stick with almost any desired linux distribution.
So, there are 2 alternatives, try different flasher commands or try flashing with Linux.
You may also try another computer. The problem seems to be in establishing the USB connection for whatever reason. I've had a case of the N900 (yes, I know, a different best) consistently refusing to flash on 3 different PCs in the house using 5 different OSes. Then I tried on the 4th machine and it went smoothly as butter.
I have gone through this situation and i would suggest u to use original nokia cable, next open you n9 and try to remove the proximity sensor and then boot the phone i am sure it will boot up. This solution i found after 5 month of n9 being dead. I had the same issues. try this 2 solutions and i am sure one of these should work
