My uploaded files are corrupt (.zip.cpgz) and I'm receiving errors when I update products

I'm working on a completely updated copy of the plugin.

When I go to add a new Product or edit an existing Product, I am confronted with the following error:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'save_custom_meta_data' not found or invalid function name in /nfs/c11/h01/mnt/200124/domains/psdbooster.com/html/wp-includes/plugin.php on line 496

Warning: Cannot modify header information - headers already sent by (output started at /nfs/c11/h01/mnt/200124/domains/psdbooster.com/html/wp-includes/plugin.php:496) in /nfs/c11/h01/mnt/200124/domains/psdbooster.com/html/wp-admin/post.php on line 233

Warning: Cannot modify header information - headers already sent by (output started at /nfs/c11/h01/mnt/200124/domains/psdbooster.com/html/wp-includes/plugin.php:496) in /nfs/c11/h01/mnt/200124/domains/psdbooster.com/html/wp-includes/pluggable.php on line 1178

Once I refresh the Products listing, the listing will then be there, but any files I uploaded to protect are corrupt. .zip files just unzip as .zip.cpgz.

Do I have folder permissions wrong or is this another issue? Thanks.