Oracle Database Discussions

Hello,
I am using Oracle database 11g and RHEL5.

I am having 3 DB's - DB1 ,DB2 and DB3.

I have DB link's from DB1 -> DB3 and DB2 -> DB3.

When i fire a update statement in DB1/DB2 which has a sub-query in it. The sub-queries tables is as TAB_NAME@DB3. The table is from DB3 and i have to refer it with the help of the DB link.

But I get the error as ORA-12541:No listener.

even if i fire this for any other table of DB3 , i get the same error.

I suffered on net and found some solutions but none worked for me.

I checked the listener, its running.

Please guide me for solution. If i have missed some basic checking steps please let me know.

Thanks in advance.