Funny failure when using EMWIN
C:\Users\bennacef\Desktop\SVN\STM32_emWin_Library\Branches\STemWin_Binray_Generator\Firmware\Project\STemWin528_20150626\TrueSTUDIO\CM7\Debug/..........\Utilities\Third_Party\STemWin528_20150626\GUI\Core\GUI_Core.c
Have you opened TrueSTUDIO project with SystemWorkbench ?
note:
after path simplification : the file path become >> C:/Users/bennacef/Desktop/SVN/STM32_emWin_Library/Branches/STemWin_Binray_Generator/Firmware/Utilities/Third_Party/STemWin528_20150626/GUI/Core/GUI_Core.c
you need to ensure that this file exists