Ignore them. There is no dstash.dll
They are trying to refer to dstorage.dll. And you can either rename it, move it, or just delete it.
However, you can also do this instead:
Go to the gear cog to the right of the play button for Diablo IV in the Battlenet App.
Go to “Game Settings”
Click the “Additional command line arguments” box.
Add
-disableds
Click “Done” Then you won’t have to mess with files at all.