When installing most if not all versions of IBM Portal on Linux, to get the installer to run you need to install a couple of extra packages:
Depending on the options you chose when first installing Linux there may be more – the easiest way to find them is to know that the graphical installer sends it’s error messages to /tmp/wpinstalllog.txt. It’s usually fairly easy to match the error messages up to the package you need to install to fix it.
Don’t be put off by the fact that it prints an error about not being able to connect to the X server to the terminal – that’s usually a red herring. Open an xterm instance to confirm the connection to the X server works and then go back to tracking down missing packages.