Need help using copy in the manifest.php

I have the used "copy" in another package that builds a module and it works fine.  Now I am trying to use "copy" in a package all by itself and I get a "Failed to copy cache/upgrades/temp/bEJWuG/Files/custom/Extension/application/Ext/EntryPointRegistry/UpdateClassTimeFields.php to custom/Extension/application/Ext/EntryPointRegistry/UpdateClassTimeFields.php"

Please help. I need this to work for a project that ends soon.