1) Create a new data connection to the folder where your qvf is located, following these steps:}
1.a) Go to "Script Editor"
1.b) Click on "Create new connection" > "Folder"
1.c) Create a connection to the location of your source app (it should be something on the line of C:\Users\<your_user_name>\Documents\Qlik\Sense\Apps )
2) Check if you have access to your source document (that the location is right and it does not have section access blocking you)
3) Create the binary load line (should be the very first line in your load script) , something like this: