I'm building on a Solaris slave trying to access a CVS repository over SSH connection
Private key location is set to $SSH_PRIVATE_KEY_DIR/id_rsa
and known hosts to $SSH_PRIVATE_KEY_DIR/known_hosts

On the slave, SSH_PRIVATE_KEY_DIR is set to:
/export/home/cxt2tst/.ssh

Checkout is done properly:
Building remotely on picard in workspace /export/home/cxt2tst/HUDSON/workspace/server.8.0
cvs update -d -P -r HEAD -D 14 May 2012 14:17:28 +0200 server.8.0
cvs update: Updating server.8.0
cvs update: Updating server.8.0/configuration
....
....

but when it tries to get the ChangeLog, an exception is raised with the following stack trace
FATAL: CVS authentication failure while running rlog command
java.lang.RuntimeException: CVS authentication failure while running rlog command
at hudson.scm.CVSSCM.getRemoteLogForModule(CVSSCM.java:530)
at hudson.scm.CVSSCM.calculateChangeLog(CVSSCM.java:414)
at hudson.scm.CVSSCM.checkout(CVSSCM.java:821)
at hudson.model.AbstractProject.checkout(AbstractProject.java:1218)
at hudson.model.AbstractBuild$AbstractRunner.checkout(AbstractBuild.java:586)
at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:475)
at hudson.model.Run.run(Run.java:1434)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:239)
Caused by: org.netbeans.lib.cvsclient.connection.AuthenticationException: SSH connection failed.
at org.netbeans.lib.cvsclient.connection.SSHConnection.open(SSHConnection.java:134)
at org.netbeans.lib.cvsclient.Client$1.run(Client.java:374)
at java.lang.Thread.run(Unknown Source)
Caused by: com.jcraft.jsch.JSchException: java.io.FileNotFoundException: \export\home\cxt2tst\.ssh\id_rsa (The system cannot find the path specified)
at com.jcraft.jsch.IdentityFile.newInstance(IdentityFile.java:98)
at com.jcraft.jsch.JSch.addIdentity(JSch.java:224)
at com.jcraft.jsch.JSch.addIdentity(JSch.java:218)
at org.netbeans.lib.cvsclient.connection.SSHConnection.open(SSHConnection.java:128)
... 2 more
Caused by: java.io.FileNotFoundException: \export\home\cxt2tst\.ssh\id_rsa (The system cannot find the path specified)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(Unknown Source)
at java.io.FileInputStream.<init>(Unknown Source)
at com.jcraft.jsch.IdentityFile.newInstance(IdentityFile.java:83)
... 5 more

It seems it cannot find the file due to the use of wrong path separator