How to fix flashing problem

Dear supporter i got three sets of lg F200S …i got KDZ firmware ,,,know trying to flash these phones with lg android tool 2014 ,,,, BUT ALWAYS GIVES ERROR ON ONE STAGE THAT PROBLEM WITH COMMUNICATION BETWEEN CELL PHONE AND PC,,,anybody can guide me that HOW TO FIX IT ? and how can i flash it sucessfully ?

waiting for kind replies,,,