I received this error when trying to install Oracle 10.2g on AIX 5.3. All Oracle requirements were met, so it didn't make sense. Turned out it missed the fonts on my CygWin - X op Windows installation.

Error:

Starting Oracle Universal Installer...

No pre-requisite checks found in oraparam.ini, no system pre-requisite checks will be executed.
Preparing to launch Oracle Universal Installer from /tmp/OraInstall2009-06-17_11-07-38AM. Please wait ...bash-3.2$ 

Warning: Cannot convert string "-*-lucida-medium-r-*-*-*-*-*-*-*-*-iso8859-1" to type FontStruct
Exception in thread "main" java.lang.InternalError: java/langNullPointerException
        at sun.awt.motif.MComponentPeer.pSetFont(Native Method)
        at sun.awt.motif.MComponentPeer.setFont(MComponentPeer.java:308)
        at sun.awt.motif.MComponentPeer.initialize(MComponentPeer.java:236)
        at sun.awt.motif.MComponentPeer.init(MComponentPeer.java:279)
        at sun.awt.motif.MWindowPeer.init(MWindowPeer.java:123)
        at sun.awt.motif.MFramePeer.<init>(MFramePeer.java:91)
        at sun.awt.motif.MToolkit.createFrame(MToolkit.java:301)
        at java.awt.Frame.addNotify(Frame.java:502)
        at java.awt.Window.pack(Window.java:473)
        at oracle.sysman.oio.oioc.OiocOneClickInstaller.createCenterPanel(OiocOneClickInstaller.java:802)
        at oracle.sysman.oio.oioc.OiocOneClickInstaller.init(OiocOneClickInstaller.java:409)
        at oracle.sysman.oio.oioc.OiocOneClickInstaller.createFrameElements(OiocOneClickInstaller.java:365)
        at oracle.sysman.oio.oioc.OiocOneClickInstaller.main(OiocOneClickInstaller.java:2171)

This is how to check if the required fonts are installed:

C:\cygwin\bin>cygcheck -c -d | grep font
fontconfig              2.6.0-1
ghostscript-fonts-other 6.0-1
ghostscript-fonts-std   8.11-1
libfontconfig1          2.6.0-1
libfontenc1             1.0.4-2

As you can see, no fonts…

I changed my own howto on installing CygWin - X op Windows, and after also installing the correct fonts it worked, and this is, how the previous command output looks like when the fonts are installed:

C:\cygwin\bin>cygcheck -c -d | grep font
font-bh-dpi75                  1.0.0-1
font-bh-lucidatypewriter-dpi75 1.0.0-1
font-encodings                 1.0.2-1
fontconfig                     2.6.0-1
ghostscript-fonts-other        6.0-1
ghostscript-fonts-std          8.11-1
libfontconfig1                 2.6.0-1
libfontenc1                    1.0.4-2
mkfontdir                      1.0.4-1
mkfontscale                    1.0.5-1