Two things –
First, I just experienced this issue. I used the plugin to backup a site on BlueHost, and Migrate it to Godaddy. I just migrated a site from one server to another, and it seems that the plugin wants to make a folder but can’t. The previous answer is correct in that the new folder and the old folder will not have the same paths (different servers) therefore setting permissions won’t fix the problem. The restore paths will be different…so that doesn’t work.
Here’s the fix:
Second, if you can connect via FTP, you can delete the backup plugin folder. Should be: wp-content/plugins/backup. Ditching those core files for the plugin will remove all php references and calls that generate the error. That will re-enable your site, assuming everything else is ok, and will eliminate the error from taking over your installation.
I was able to do this, log in, and reinstall the Backup plugin…return to business as usual.
Good luck!
