I am getting CVS authentication problem while doing cvs checkout through slave. below is the error :

Started by user CC Manager
Building remotely on Devil5 in workspace /home/tuxdev12/workspace/VFTOMCAT-Tuxedo
Using locally configured password for connection to :ext:vvaid@adeebkbs:/sharedcc/cvs/vftom2
cvs checkout -D 05 Sep 2014 10:07:52 +0200 -d vf_tomcat vf_tomcat
ERROR: CVS Authentication failed: null
org.netbeans.lib.cvsclient.connection.AuthenticationException: SSH connection failed.
at org.netbeans.lib.cvsclient.connection.SSHConnection.open(SSHConnection.java:141)
at org.netbeans.lib.cvsclient.Client$1.run(Client.java:374)
at java.lang.Thread.run(Thread.java:619)
Caused by: com.jcraft.jsch.JSchException: java.io.FileNotFoundException: /devusers/mn/csm/ngupta4/.ssh/id_rsa (No such file or directory)
at com.jcraft.jsch.KeyPair.load(KeyPair.java:524)
at com.jcraft.jsch.IdentityFile.newInstance(IdentityFile.java:40)
at com.jcraft.jsch.JSch.addIdentity(JSch.java:389)
at com.jcraft.jsch.JSch.addIdentity(JSch.java:370)
at org.netbeans.lib.cvsclient.connection.SSHConnection.open(SSHConnection.java:135)
... 2 more
Caused by: java.io.FileNotFoundException: /devusers/mn/csm/ngupta4/.ssh/id_rsa (No such file or directory)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(FileInputStream.java:106)
at java.io.FileInputStream.<init>(FileInputStream.java:66)
at com.jcraft.jsch.Util.fromFile(Util.java:492)
at com.jcraft.jsch.KeyPair.load(KeyPair.java:521)
... 6 more
ERROR: Cvs task failed
Finished: FAILURE

if i do the same through master it gets successful. After having several different combinations, resolution is that slave failed to set CVSROOT with ext option due to which it through error.