Question about connection java and Postgresql in Linux

I am trying to use Redhat Linux 9, J2sdk 1.4.2 and Postgresql 7.3.2 to
do my setting. But, I cannot access the database to set/get data
through the java program. Please help give me some suggestions.
Here is what my setting and problems:
http://hk.geocities.com/daisy_nhy/java_postgresql2.html

Thanks