刷新后Kml层工作正常，但是给出了typeError：无法读取属性getMap。在第一次加载

Hello this is the first time i am working with kml. everything running smoothly until I redirection came into place. if I hit the page directly then all works fine, but if I redirect the user form other page like login to my map page the kml layer doesn't work and give the error I above mentioned. but after I refresh the page all goes right. here is my kml code which work after one refresh.Hello this is the first time i am working with