Uploading says 'Album Is Empty'

[CherryTree.]

My apologies if this issue has already been raised, but I couldn't find anything exactly the same.

This is my gallery: http://www.dianavickersdaily.com/gallery/index.php
And my issue is that I cannot upload this one folder to the gallery for some reason, everything else adds fine.
They're uploaded fine to the FTP, and batch-add finds them fine, however when I click 'OK' no preview pictures appear (Untitled), so I tried inserting the files anyway but it then says 'album is empty' (Untitled 2). I've ensured no special characters are in the title too but it still won't work.

Any help is appreciated.

[Αndré]

Set permissions and ownership accordingly.

[CherryTree.]

All permissions are set to 777, and I followed the 'Enable troubleshooting settings' using a demo picture and the error message attached was shown.

[Αndré]

The path to your ImageMagick 'convert' application is wrong. Set it correctly or use GD2 (you can choose between them in Coppermine's config).

[CherryTree.]

Thanks very much, it has let me add them now.