Cannot flash lg-h815

Hello, i have an LG-H815 mobile stuck on boot screen and im trying to flash it with LG Flash Tool 2014. I installed the drivers LGMobileDriver_WHQL_Ver_4.0.4_2 and connected the phone in download mode. Selected CS_EMERGENCY and the kdz file: H81520B_00.kdz. Now i try to CSE Flash and selected START. Then the process starts and i get "connection to server failed". I think driver problem.....check the attachment
Help....

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