There is a newer method to flash the Edison module. This new method uses a software called Flash Tool Lite. This software flashes the latest Yocto image for Edison. You can download it from the following site under the Flash Tool Lite section: IoT - Intel® Edison Board Download | Intel® Developer Zone. A user's guide can be found in the same section as well.
I recommend you to check the following document for additional details: Flashing the Edison Module. This document explains the methods to flash the Edison module, and mentions the old method (the one that you are trying to do) and the new one. It might be interesting for you.