RMAN error: RMAN-03022 and ORA-03114 error

I am getting this RMAN-03022 and ORA-03114 error:

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of allocate command at 19/13/2015 21:13:22
ORA-03114: not connected to ORACLE

How do I fix this ORA-03114 and RMAN-03002 error?

Option 1) Try flushing the shared as below and check whether it is working now.

Connect to the database and execute the below

sql>alter system flush shared_pool;

Once the shared pool is flushed RMAN should start working.

If the above doesn't help, try next step

Option 2) 

sql>alter system set cursor_sharing=exact scope=both;