Multisite Content Copier Error

Hi. I have made several attempts to copy a small number of posts from my site (site id 2) to my site (site id 6) using the Multisite Content Copier plugin. Each time, nothing was copied. However, twice when going to the destination site to check whether the content had copied, I received this error message:

Fatal error: Call to undefined function wp_generate_attachment_metadata() in /home/blogweb/public_html/wp-content/plugins/multisite-content-copier/inc/content-copier/content-copier-post-type.php on line 548

When I refresh the browser page, I see the admin interface as usual.

Please let me know why the Multisite Content Copier is not working.

Thank you,


P.S. The other WPMU plugins I have installed and in use are:

Domain Mapping


Google Maps