Make not working (on RHE)

I am installing postgres 7.3.4 on a RedHat Enterprise box but 'make'
refuses to work. When installing as user postgres I get the following
error message:
------------------------------------
driver:
[copy] Copying 1 file to
/usr/local/src/postgresql-7.3.4/src/interfaces/jdbc/org/postgresql
[echo] Configured build for the JDBC3 edition driver

compile:
[javac] Compiling 52 source files to
/usr/local/src/postgresql-7.3.4/src/interfaces/jdbc/build
[javac]
/usr/local/src/postgresql-7.3.4/src/interfaces/jdbc/org/postgresql/jdbc3/Jdbc3PoolingDataSource.java:29:
error: Method
`org.postgresql.jdbc2.optional.PoolingDataSource.getDataSource(java.lang.String)'
was defined with return type
`org.postgresql.jdbc2.optional.PoolingDataSource' in class
`org.postgresql.jdbc2.optional.PoolingDataSource'.
[javac] static Jdbc3PoolingDataSource getDataSource(String name)
[javac] ^
[javac] 1 error

BUILD FAILED
file:/usr/local/src/postgresql-7.3.4/src/interfaces/jdbc/build.xml:104:
Compile failed; see the compiler error output for details.
------------------------------------

I have already removed all traces of postgres which were installed as
well as the rh-postgresql3.jar file. Currently I do not have the
classpath set.

Java version:
java version "1.4.2_01"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_01-b06)
Java HotSpot(TM) Client VM (build 1.4.2_01-b06, mixed mode)
Ant version: 1.5.3-1

I have also tried postgres 7.4.1 with the same error(slightly different).

I have found a few references to this, the most promising has a response
from Kris Jurka which says that the postgresql.jar file may still be
hanging around somewhere, but it is totally removed from my system.

Can anyone help?

ps I also tried to copy the latest jdbc3 driver from jdbc.postgresql.org
and place it in the classpath, but it still didn't work.
pps my configure params:
./configure --enable-multibyte \
--enable-odbc \
--with-java \
--with-maxbackends=96 \
--enable-syslog