Tivoli Storage Manager Admin Center on rhel5

If you install the ISC and Admin Center for Tivoli Storage Manager on a RHEL5 box and you get the "portlet unavailable" error try installing libXp
$ yum install libXp
then stopping and starting the ISC again (by default $isc_home is /opt/IBM/ISC601/):
cd $isc_home/PortalServer/bin
./stopISC.sh ISC_Portal iscadmin iscpassword

check for runaway processes
$ ps -ef | grep -i java

Then startup the the ISC again...
./startISC.sh ISC_Portal