You need to:

use Project::Client::Node::TestNode;
[download]

in client.pl, or else the new subroutine never hits the symbol table. Perl will not go out and find packages just because you try to use a method in them. You must explicitly load them.
UPDATE: I missed the requires in the parent classes. I tend to use use base, which does the requires automatically.
Hope this helps.

-pete
"I am Jack's utter lack of disbelief"