A fix for new multisite installs

WordPress now dont have the $base parameter when installing multisites.

I edited

if( is_subdomain_install() ) {
				$newdomain = $domain.".".$current_site->domain;
				$path = $base;
			} else {
				$newdomain = $current_site->domain;
				$path = trailingslashit($base.$domain);
			}

And changed it to:

if( is_subdomain_install() ) {
				$newdomain = $domain.".".$current_site->domain;
				$path = $current_site->path;
			} else {
				$newdomain = $current_site->domain;
				$base = $current_site->path;
				$path = trailingslashit($base.$domain);
			}

And it worked for me.

Suggest you update the plugin.

http://wordpress.org/plugins/blog-copier/