My guess is that your install program is not seeing the Sun Java, since it appears you have the gcc Java loaded.
Though I appreciate the gcc java attempt, I wouldn't be suprised if it makes life difficult.
In Sun's java, there's an environment variable which points to your java directories - JAVA_HOME - and is usually something like /usr/bin/java.
On my system I have the following:
JAVA_HOME=/usr/lib/jvm/java
JAVA_ROOT=/usr/lib/jvm/java
JDK_HOME=/usr/lib/jvm/java
JRE_HOME=/usr/lib/jvm/java/jre
If you want the location on your system, type at a command prompt (sorry, it can't be helped):
echo $JAVA_HOME
You should get something like the following:
kai@yoda:~> echo $JAVA_HOME
/usr/lib/jvm/java
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