Hi @uchan,
For any recent version of Android the path to internal user storage is "/storage/emulated/0/". Usually there is some link for convenient access (In your case: "/sdcard/"). The absolute path is always valid in the end point. Not mandatory all intermediate folder are visible!
Hope this helps.
PS: Seems you have forgetted a "data" part of the path! In the user directory, path should look like: "Android/data/com.dropbox.android/files/uxxxxxxxxx/scratch/". 