Rekordbox not copying files after moving database 'E-8302' error

Hello,

I just moved my Rekordbox database and all files to a new external hard drive as the one I had been using was full. Have no issues with making new playlists and editing existing ones, but when I add new songs/files to the library HD and then sync and eject to the flash drive I will be playing from the new songs (i.e. the ones not previously stored on my old HD) have not copied over and the CDJs give me an 'E-8302' error.

These files appear to be fine within Rekordbox, the preview and play but upon looking at the path names of the files in Rekordbox I can see that the new songs are not being copied over to the flash drive during sync. Any help would be appreciated, thanks.