A lot of users report issues not being able to flash rom's on 4.4.2 kitkat.

A fix is to downgrade to 4.3, then flash roms.

I dont know why. I bought my device upgraded to 4.4.2 already, and i can flash roms with no issues.

Search the forum for the topic and you will find the info you need.
Phones: Motorola Atrix 4G ---> Samsung Galaxy Nexus (temporarily) ---> LG Optimus 3d ---> Samsung Galaxy SII LTE Skyrocket ---> LG Optimus G ---> Sony Xperia ZL ---> Motorola Moto G
My Roms/Ports: CarbonRom/CarbonClash (port): http://forum.xda-developers.com/show....php?t=2181390
Thanks: XDA and all its members. Without you I'd still be an uneducated bumpkin complaining about my shi**y phone.