The translators getting duplicated is clearly the sign of ArchiCAD not having the permission to overwrite the original instance. You should check whether all folders in the path to the mounted volume allow full access for the clients:
- Right click on the Folder
- Get Info
- in Sharing & Permissions section change the permission to "Read & Write" for everyone.
Hope this helps,
Csaba
Csaba Kézér VP, Global Customer Support Graphisoft