I just want to check if you have set the baud rate properly.If the baud rate is correct, then can you try a lower baud rate and check if the bootloading is working fine in that baud rate.You will need to change the buad rate in the bootloader project as well.
We are experiencing the same issue. Bootloader in PSoC creator works fine but the .exe in AN68272 keeps giving error 4 or hangs. Were you able to find a resolution? We are using 3.3 SP3.