So if your parameters matched the function is working, but the data is not being fed into OrgChart correctly.
I'd next try a couple of things...
First restart the application in NetWeaver Admin. There's some caching such that if the function is modified you need to restart the app to pick up the changes. Maybe something in the cache is corrupt such that a restart could clear it.
If the issue persists after a restart, try creating a new out if the box build - i.e. just SAP connection strings, authentication and root IDs set. This should highlight if it is related to your configuration or to the app/install.
I haven't seen anyone else posting here with similar issues on 4.1 (I've not worked on 4.1 just yet) so it would seem more likely to be a localised issue.