When I try to start a slave on my linux vm centos 5 i have, this log :

[05/20/10 15:29:43] [SSH] Opening SSH connection to 192.25.204.50:22.
[05/20/10 15:29:43] [SSH] Authenticating as root/******.
[05/20/10 15:29:43] [SSH] Authentication successful.
[05/20/10 15:29:44] [SSH] The remote users environment is:
BASH=/bin/bash
BASH_ARGC=()
BASH_ARGV=()
BASH_EXECUTION_STRING=set
BASH_LINENO=()
BASH_SOURCE=()
BASH_VERSINFO=([0]="3" [1]="2" [2]="25" [3]="1" [4]="release" [5]="i686-redhat-linux-gnu")
BASH_VERSION='3.2.25(1)-release'
COLORS=/etc/DIR_COLORS
CVS_RSH=ssh
DIRSTACK=()
EUID=0
GROUPS=()
G_BROKEN_FILENAMES=1
HOME=/root
HOSTNAME=boedig.ipsis.com
HOSTTYPE=i686
IFS=$' \t\n'
KDEDIR=/usr
KDE_IS_PRELINKED=1
KDE_NO_IPV6=1
LANG=fr_FR.UTF-8
LESSOPEN='|/usr/bin/lesspipe.sh %s'
LOGNAME=root
LS_COLORS=
MACHTYPE=i686-redhat-linux-gnu
MAIL=/var/mail/root
OPTERR=1
OPTIND=1
OSTYPE=linux-gnu
PATH=/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
PIPESTATUS=([0]="0")
PPID=5349
PRELINKING=yes
PRELINK_FULL_TIME_INTERVAL=14
PRELINK_NONRPM_CHECK_INTERVAL=7
PRELINK_OPTS=-mR
PS4='+ '
PWD=/root
SHELL=/bin/bash
SHELLOPTS=braceexpand:hashall:interactive-comments
SHLVL=1
SSH_ASKPASS=/usr/libexec/openssh/gnome-ssh-askpass
SSH_CLIENT='192.25.204.40 4057 22'
SSH_CONNECTION='192.25.204.40 4057 192.25.204.50 22'
TERM=dumb
UID=0
USER=root
_=/etc/bashrc
consoletype=serial
tmpid=0
[05/20/10 15:29:44] [SSH] Checking java version of java
[05/20/10 15:29:44] [SSH] java -version returned 1.6.0_20.
[05/20/10 15:29:44] [SSH] Checking java version of /usr/bin/java
[05/20/10 15:29:45] [SSH] /usr/bin/java -version returned 1.6.0_20.
[05/20/10 15:29:45] [SSH] Checking java version of /usr/java/default/bin/java
[05/20/10 15:29:45] [SSH] /usr/java/default/bin/java -version returned 1.6.0_20.
[05/20/10 15:29:45] [SSH] Checking java version of /usr/java/latest/bin/java
[05/20/10 15:29:46] [SSH] /usr/java/latest/bin/java -version returned 1.6.0_20.
[05/20/10 15:29:46] [SSH] Checking java version of /usr/local/bin/java
Couldn't figure out the Java version of /usr/local/bin/java
bash: /usr/local/bin/java: Aucun fichier ou répertoire de ce type

[05/20/10 15:29:46] [SSH] Checking java version of /usr/local/java/bin/java
Couldn't figure out the Java version of /usr/local/java/bin/java
bash: /usr/local/java/bin/java: Aucun fichier ou répertoire de ce type

[05/20/10 15:29:47] [SSH] Checking java version of /home/hudson/jdk/bin/java
Couldn't figure out the Java version of /home/hudson/jdk/bin/java
bash: /home/hudson/jdk/bin/java: Aucun fichier ou répertoire de ce type

[05/20/10 15:29:47] [SSH] Checking java version of /usr/java/jdk1.6.0_20/bin/java
[05/20/10 15:29:47] [SSH] /usr/java/jdk1.6.0_20/bin/java -version returned 1.6.0_20.
Linux boedig.ipsis.com 2.6.18-194.3.1.el5 #1 SMP Thu May 13 13:09:10 EDT 2010 i686 i686 i386 GNU/Linux
Choosing the download bundle
Downloading JDK6u16
Installing /home/hudson/jdk.sh
[jdk] $ /home/hudson/jdk.sh -noregister
bash: line 0: cd: \home\hudson\jdk: Aucun fichier ou répertoire de ce type
hudson.util.IOException2: Could not find any known supported java version in [java, /usr/bin/java, /usr/java/default/bin/java, /usr/java/latest/bin/java, /usr/local/bin/java, /usr/local/java/bin/java, /home/hudson/jdk/bin/java, /usr/java/jdk1.6.0_20/bin/java], and we also failed to install JDK as a fallback
at hudson.plugins.sshslaves.SSHLauncher.launch(SSHLauncher.java:200)
at hudson.slaves.SlaveComputer$1.call(SlaveComputer.java:183)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
Caused by: hudson.AbortException: Failed to install JDK
at hudson.tools.JDKInstaller.install(JDKInstaller.java:161)
at hudson.plugins.sshslaves.SSHLauncher.attemptToInstallJDK(SSHLauncher.java:285)
at hudson.plugins.sshslaves.SSHLauncher.launch(SSHLauncher.java:198)
... 6 more
[05/20/10 15:35:01] [SSH] Connection closed.

The problem seems to be an error in checking java version, i have a valid jdk installed.

May be the ligne NumberFormat.getInstance().parse could not parse correctly the string 1.6.0_20 due to _.