UMX V351 unlock problem

hello team!

i got this cheap phone, its rooted but when i try to unlock i got problems. There’s anyway to unlock it or any solution for that?

my log:

——— 2015-12-23 12:01:54 ———
SigmaKey 2.14.03 ADB: Direct unlock
* daemon not running. starting it now *
* daemon started successfully *
^ ROMaster Composite ADB Interface
Version: Linux version 3.10.17-svn853 (mating@mtk-ui1) (gcc version 4.7 (GCC) ) #1 PREEMPT Wed Aug 5 17:50:17 CST 2015
Phone model: Spreadtrum SN357
Android 4.4.2; Firmware: MocorDroid; Date: Wed Aug 5 17:45:06 CST 2015
Version: SN357_UMX_V07_20150806
Baseband Firmware: TM_BASE_13C_W14.41_MP_W15.05_P1|sc7715_sc7715_mode m|02-02-2015 11:19:48
Baseband Processor: scx15
Version: SN357_UMX_V07_20150806
–>>>Reading data…File I/O operation failed <<<–

any suggestion is welcome
thanks B.R