Ok for anybody experiencing problems making this work on the DNS320L here is the work around:
works well if you experience adding your library address and it disapears:
Uninstall original Serviio (if installed)
RESTART DNS320L >SYSTEM>RESTART
Install serviio
Add key
Enable Serviio in share center
RESTART DNS320L AGAIN
Run servio config
hit configure>remote>add password
hit Library and add your Library Location.
Save and exit.
If you do it in this exact way serviio runs perfectly, although on the DNS320L its not as fast as say Twonky Server...