The problem is that you put the MAIN firmware to wrong place(Firmware upgrade pack box).Flashing upgrade archive: D:\Downloaded Programs\Sony Ericsson\SETOOL2LITE\Firmware\Use these\W600_R7CA017_FS_AMERICA_1_RED49\W600_R7CA017 _FS_AMERICA_1_RED49.fbn
Check out the Flash your phone using SETool 2 Lite tutorial, and follow it carefully.