"Could not connect to the database" error during Satellite installation

Issue

• Getting error during Satellite installation:

Database: Setting up database connection. 
Could not connect to the database.  Your connection information may be
incorrect.  Error: DBI connect('rhnsat','rhnsat',...) failed:
ORA-12545: Connect failed because target host or object does not exist
(DBD ERROR: OCIServerAttach) at (eval 10) line 1391     

• Or

TNSLSNR for Linux: Version 10.2.0.4.0 - Production          
Log messages written to /opt/apps/oracle/web/product/10.2.0/db_1/network/log/listener.log  
Error listening on: (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))  
TNS-12545: Connect failed because target host or object does not exist  
TNS-12560: TNS:protocol adapter error    
TNS-00515: Connect failed because target host or object does not exist     
Linux Error: 11: Resource temporarily unavailable