How to reduce the size of Windows Package for a project?

I Use this command.
E:\Program Files\Epic Games\4.7\Engine\Binaries\Win64>UnrealPak C:\Users\zhouyl
Desktop\WindowsNoEditor\ExportTest\Content\Paks\ -List > e:/PakList1.txt.
But in the PakList1.txt ,Its content is “LogWindows:Error: Windows GetLastError: ??? (0)”.

when i set package setting " Use Pak File" be unchecked .Then i can see the packed files in exported files
It is only the map file taking big space.!But i cannot see what is in this file …why it is so big .?[alt text][1]

It is a so simple level .There’s no so many static lighting baked in…you dont know why? i’m confused too