The concept of "root" does not apply to RTOS feature phones. You cannot install Android apps on it. The flash tool simply restores the original OS.
Always verify the checksum (MD5) of your downloaded file. The flash tool will often auto-check this. If it says "Invalid MD5," delete the file and download again. Samsung E1200t Flash File Tool
If your PC makes a "USB connect sound" when you plug the phone in, there is hope. Use a or a RIFF Box . If no sound, the battery or charging port is dead. The concept of "root" does not apply to RTOS feature phones