in reply to Modules included more than once

Subroutine XXXX redefined at line 1584

which forms a list of all subroutines in YYYY. This implies that the package is being included more than once.

What I would like to know is if there is any way to stop this happening, or will I just have to live with the warnings? The feature I have in mind is similar to the PHP command 'require_once'.

You shouldn't have to remove those interdependencies. They shouldn't matter.

What platform? Windows? I bet it is.

My guess is that there's a problem with the case. If you do

use Foo; use foo;
on Windows, that will indeed load twice, as is the same file.

Just use the proper case everywhere.