The one way I found around this was to upload directly through C-panel. I tried changing permissions and a bunch of other things but never could avoid getting the “The uploaded file could not be moved to….” error message. When you go to the file manager in c-panel drill down to the file you want inside the wp-content file and upload it there. This even work with plugin zip files that also gave me headaches. Just extract the zip files after upload.
Hope this helps
Jimmy
Work From Home