Error Downgrade. help-me

Good morning, upgraded to CM12 and now want to downgrade ... I'm using flash tool drivers all installed ... place I hang up the process ... the error

Code:

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02/044/2015 07:44:56 - INFO - Flashtool Version 0.9.19.8 built on 24-09-2015 22:00:00
02/044/2015 07:44:56 - INFO - Executing search strategies to find proxy selector
02/045/2015 07:45:04 - INFO - No proxy found for IE. Trying next one
02/045/2015 07:45:04 - INFO - Strategy firefox failed trying next one : No Firefox installation found
02/045/2015 07:45:04 - INFO - No proxy found for java. Trying next one
02/045/2015 07:45:06 - INFO - Syncing devices from github
02/045/2015 07:45:09 - INFO - Scanning devices folder for changes.
02/046/2015 07:46:42 - INFO - Changes have been found. Doing a hard reset (removing user modifications).
02/046/2015 07:46:48 - INFO - Pulling changes from github.
02/046/2015 07:46:51 - INFO - Devices sync finished.
02/047/2015 07:47:04 - INFO - Device disconnected
02/047/2015 07:47:08 - INFO - Selected Bundle for Sony Xperia M Dual (C2004). FW release : 15.5.A.0.18. Customization : Unbranded Brazil
02/047/2015 07:47:08 - INFO - Preparing files for flashing
02/050/2015 07:50:53 - INFO - Please connect your device into flashmode.
02/051/2015 07:51:09 - INFO - Device connected in flash mode
02/051/2015 07:51:11 - INFO - Opening device for R/W
02/051/2015 07:51:11 - INFO - Reading device information
02/051/2015 07:51:11 - INFO - Phone ready for flashmode operations.
02/051/2015 07:51:11 - INFO - Opening TA partition 2
02/051/2015 07:51:12 - INFO - Current device : Unknown: May 9 2014/12:58:25 - BY900CW2PR - Unknown: May 9 2014/12:58:25 - Unknown: May 9 2014/12:58:25 - Unknown: May 9 2014/12:58:25
02/051/2015 07:51:12 - INFO - Closing TA partition
02/051/2015 07:51:12 - INFO - Start Flashing
02/051/2015 07:51:12 - INFO - Processing loader.sin
02/051/2015 07:51:12 - INFO - Checking header
02/051/2015 07:51:12 - INFO - Flashing data
02/051/2015 07:51:12 - INFO - Loader : S1_Root_dbe9 - Version : loader_MSM8X30_10 / Boot version : S1_Boot_MSM_8227_5 / Bootloader status : ROOTED
02/051/2015 07:51:12 - INFO - Max packet size set to 512K
02/051/2015 07:51:24 - INFO - Making a TA backup
02/051/2015 07:51:24 - INFO - Opening TA partition 1
02/051/2015 07:51:24 - INFO - Start Dumping TA partition 1
02/051/2015 07:51:25 - INFO - Finished Dumping TA partition 1
02/051/2015 07:51:25 - INFO - TA partition 1 saved to C:\Users\diego\.flashTool\registeredDevices\BY900CW2PR\s1ta15-10-02_07-51-24.ta
02/051/2015 07:51:25 - INFO - Closing TA partition
02/051/2015 07:51:25 - INFO - Opening TA partition 2
02/051/2015 07:51:25 - INFO - Start Dumping TA partition 2
02/051/2015 07:51:25 - INFO - Finished Dumping TA partition 2
02/051/2015 07:51:25 - INFO - TA partition 2 saved to C:\Users\diego\.flashTool\registeredDevices\BY900CW2PR\s1ta15-10-02_07-51-24.ta
02/051/2015 07:51:25 - INFO - Closing TA partition
02/051/2015 07:51:26 - INFO - Parsing boot delivery
02/051/2015 07:51:29 - INFO - Ending flash session
02/051/2015 07:51:29 - ERROR -
02/051/2015 07:51:29 - ERROR - Error flashing. Aborted
02/051/2015 07:51:30 - INFO - Device connected in flash mode
02/051/2015 07:51:30 - INFO - Device disconnected
02/051/2015 07:51:33 - INFO - Device connected in flash mode

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can anyone help me ??