dbca fails with ORA-3114 while enabling Database Vault

Problem Description

While enabling Database Vault with DBCA the following errors are encountered :

Preparing to Configure Database
DBCA_PROGRESS : 2%
DBCA_PROGRESS : 5%
DBCA_PROGRESS : 28%
Adding Oracle Database Vault
DBCA_PROGRESS : 29%
ORA-03114: not connected to ORACLE

The same ORA-3114 error can be seen when running the DBCA GUI.

$ORACLE_BASE/cfgtoollogs/dbca/$ORACLE_SID/trace.log file shows:

...
[Thread-37] [ 2012-02-08 08:25.074 CET ] [BasicStep.configureSettings:304] messageHandler being set=null
[Thread-37] [ 2012-02-08 08:25.195 CET ] [StepContext.getATempTablespace:631] Connected to the database
[Thread-37] [ 2012-02-08 08:25.320 CET ] [SQLEngine.setSpool:1945] old Spool = null
[Thread-37] [ 2012-02-08 08:25.321 CET ] [SQLEngine.setSpool:1946] Setting Spool = /u01/oracle/cfgtoollogs/dbca/rac1/datavault.log
[Thread-37] [ 2012-02-08 08:25.321 CET ] [SQLEngine.setSpool:1947] Is spool appendable? --> true
[Thread-37] [ 2012-02-08 08:25.322 CET ] [DataVaultOptionStep.executeImpl:138] calling catmac dvownername :SECADMIN
[Thread-37] [ 2012-02-08 08:25.322 CET ] [DataVaultOptionStep.executeImpl:139] calling catmac getDVAcctMgrName() :SECACCTMGR
[Thread-35] [ 2012-02-08 08:25.447 CET ] [BasicStep.handleNonIgnorableError:430] oracle.sysman.assistants.util.UIMessageHandler@60dc4c81:messageHandler
[Thread-35] [ 2012-02-08 08:25.448 CET ] [BasicStep.handleNonIgnorableError:431] ORA-03114: not connected to ORACLE
...

Cause of the Problem
The error occurred due to Native encryption is configured. The sqlnet.ora file contains the following parameters:

SQLNET.ENCRYPTION_SERVER = required 
SQLNET.ENCRYPTION_TYPES _SERVER = (AES256)

Solution of the Problem
Remove above two encryption parameters from sqlnet.ora and then run dbca again. Problem should be resolved.