Oracle Database Express Edition (XE)

I keep getting the error ORA-28595: Extproc agent : Invalid DLL Path when trying to execute my code,
The command I typed to register the DLL is:

Create or replace library external_lib as '$ORACLE_HOME/BIN/DataCartridge.dll';
/

and the DLL exists to this directory.

What I am missing or doing wrong?

Thanks, N.