This is part of the error according to the logs ( I could not fit it all )
[2015.04.16-20.02.57:251][ 0]LogStreaming:Warning: Failed to read file ‘…/…/…/Engine/Content/Editor/Slate/WidgetCarousel/Arrow-Left.png’ error.
[2015.04.16-20.02.57:251][ 0]LogSlateD3D: Could not find file for Slate resource: …/…/…/Engine/Content/Editor/Slate/WidgetCarousel/Arrow-Left.png
[2015.04.16-20.02.57:251][ 0]LogStreaming:Warning: Failed to read file ‘…/…/…/Engine/Content/Editor/Slate/WidgetCarousel/Arrow-Right.png’ error.
[2015.04.16-20.02.57:251][ 0]LogSlateD3D: Could not find file for Slate resource: …/…/…/Engine/Content/Editor/Slate/WidgetCarousel/Arrow-Right.png
[2015.04.16-20.02.57:252][ 0]LogStreaming:Warning: Failed to read file ‘…/…/…/Engine/Content/Editor/Slate/WidgetCarousel/WhiteBox_7px_CornerRadius.png’ error.
[2015.04.16-20.02.57:252][ 0]LogSlateD3D: Could not find file for Slate resource: …/…/…/Engine/Content/Editor/Slate/WidgetCarousel/WhiteBox_7px_CornerRadius.png
[2015.04.16-20.02.57:252][ 0]LogStreaming:Warning: Failed to read file ‘…/…/…/Engine/Content/Editor/Slate/WidgetCarousel/WhiteBox_7px_CornerRadius.png’ error.
[2015.04.16-20.02.57:252][ 0]LogSlateD3D: Could not find file for Slate resource: …/…/…/Engine/Content/Editor/Slate/WidgetCarousel/WhiteBox_7px_CornerRadius.png
[2015.04.16-20.02.57:252][ 0]LogStreaming:Warning: Failed to read file ‘…/…/…/Engine/Content/Editor/Slate/WidgetCarousel/WhiteBox_7px_CornerRadius.png’ error.
[2015.04.16-20.02.57:252][ 0]LogSlateD3D: Could not find file for Slate resource: …/…/…/Engine/Content/Editor/Slate/WidgetCarousel/WhiteBox_7px_CornerRadius.png
[2015.04.16-20.02.57:252][ 0]LogStreaming:Warning: Failed to read file ‘…/…/…/Engine/Content/Editor/Slate/WidgetCarousel/CarouselNavMarker.png’ error.
[2015.04.16-20.02.57:252][ 0]LogSlateD3D: Could not find file for Slate resource: …/…/…/Engine/Content/Editor/Slate/WidgetCarousel