help xperia tipo flashing

hello all
i tried to flash cm10 in my tipo but its now stuck in sony logo i thing because it wasnt rooted but now am trying to instal the official firmware but it says error Error in processHeader

please help just tell me what 2 do

18/056/2013 17:56:22 - INFO - Selected st21i_11.0.A.4.22_Generic.ftf
18/056/2013 17:56:22 - INFO - Preparing files for flashing
18/056/2013 17:56:23 - INFO - Device disconnected
18/056/2013 17:56:29 - INFO - Please connect your device into flashmode.
18/056/2013 17:56:32 - INFO - Device connected in flash mode
18/056/2013 17:56:33 - INFO - Opening device for R/W
18/056/2013 17:56:33 - INFO - Reading device information
18/056/2013 17:56:33 - INFO - Phone ready for flashmode operations.
18/056/2013 17:56:33 - INFO - Current device : ST21i - BX903A8PKJ - 1264-6866_R7D - 1261-1516_11.0.A.4.22 - WORLD-i_11.0.A.4.22
18/056/2013 17:56:33 - INFO - Start Flashing
18/056/2013 17:56:33 - INFO - Processing loader
18/056/2013 17:56:33 - INFO - Ending flash session
18/056/2013 17:56:33 - ERROR - Error in processHeader
18/056/2013 17:56:33 - ERROR - Error flashing. Aborted
18/056/2013 17:56:33 - INFO - Device connected in flash mode
thanx all