Opensso/cli ssoadm - The version of your server instance is: null

Symptom:
--------
Cli ssoadm setup ends with exception
Eg
-bash-3.00$ ./setup
Path to config files of OpenSSO server (example: /opensso):/home/etggfish/opensso
Debug Directory:/home/etggfish/opensso/opensso/debug
Log Directory:/home/etggfish/opensso/opensso/log
The scripts are properly setup under directory: /local/0/sw/openssotools/opensso
Debug directory is /home/etggfish/opensso/opensso/debug.
Log directory is /home/etggfish/opensso/opensso/log.
The version of this tools.zip is: Enterprise 8.0 Build 6(2008-October-31 09:07)
The version of your server instance is: null



Solution:
---------
1) Check the com.iplanet.am.version in the server.
Thanks to Gang for the following script to set the property to the right value
You can run this script to fix null version

$SSOADM_PATH/ssoadm update-server-cfg -s default -a 'com.iplanet.am.version=' -u amadmin -f $PWF -O
SERVER=`$SSOADM_PATH/ssoadm list-servers -u amadmin -f $PWF -O`
for SVR in $SERVER
do
$SSOADM_PATH/ssoadm remove-server-cfg -s $SVR -a 'com.iplanet.am.version' -u amadmin -f $PWF -O
done

2) Also check if the attribute is present com.iplanet.am.version in the Config DS.
Else you can add it using Configuration -> Servers & Sites -> Default Server Instance -> com.iplanet.am.version attribute