thats a skylark error - you seem to have already uploaded the file to skylark and are possibly double-clicking it in the skylark file manager. That is not needed.
Once the file is uploaded to the opaks folder in skylark file manager, you are on step “g”.
In any case, the update file is now being sent over-the-air. So if your update has still not happened, you just need to wait for the update file to finish downloading on your receiver, and the update will happen automatically. Just ensure you are receiving normally.
Are you sure you are still on 5.3 though? Given that you uploaded the file to the opaks folder, update to 5.4 would have already happened.
Thats always OK. If the update (either manual, or over-the-air) doesn’t work, or fails for whatever reason, you can always burn the full image file from Archive on the same sdcard (don’t try to format/partition the sd card) and it will work fine.