You might have WebSphere Application Server - Express for iSeries preinstalled on your V5R2, V5R3, or V5R4 iSeries server. To verify whether or not WebSphere Application Server - Express is already installed on your machine, perform these steps:
go licpgm
5722E51 *BASE WebSphere Application Server - ExpressThis is what you should see if option 2 is installed:
5722E51 2 IBM WebSphere Application Server Express V5.1
If you have a preinstalled system, WebSphere Application Server - Express is already installed and an instance has been created and configured. To finish the configuration of WebSphere Application Server - Express and start your instance, see Administration considerations for preloaded systems in the Administration topic.