problem importing docman

Using DOCman plugin, i see this error. All document have this error: [fgj2wpp] Can’t copy http://www.pascuolapc.net/dmdocuments/acqua.ppt to /data/vhosts/pascuolapc.net/httpdocs/wp/wp-content/uploads/2010/07/acqua.ppt : Forbidden

I have tried to set permission on dmdocuments folder on 777 but nothing is changed.
Help me, thanks!

https://wordpress.org/plugins/fg-joomla-to-wordpress/