The normal connect string is:
Note here the / and @ have special meanings.
If yo have a user whose password is xxx@yyy, so the connect string we received is:
The code sees the first @ and takes the string following (yyy) as the TNS, and it is trying to connect to yyy.
Of course there is no such TNS entry so it will fail.
If you have verified that your ORACLE_HOME is set correctly and tnsnames.ora has correct entries then please make sure that your Spotlight's user password does not contain @ character in it.