Please read the flashing thread again:
- You are using wrong flasher binary, 3.5 is for fremantle only. Use 3.12 for Harmattan.
- There is a difference between -F and -f
- You don't need to use --erase-mmc part.

Actually if you want to reset security code, then you are trying to flash the wrong image, you cannot reset security code with only mmc image, you need to flash the main image and append --erase-user-data=secure to the flashing command. Like this:

flasher -f --erase-user-data=secure -F DFL61_HARMATTAN_40.2012.21-3.299.1_PR_LEGACY_299_ARM_RM-696_PRD_signed.bin -F DFL61_HARMATTAN_40.2012.21-3.SEAP.16_EMMC_SEAP.bin

That command takes some 10 minutes to run, but it should clear the security code. And don't use 3.5 version of the flasher, since that wont work.