ASCII to UNICODE conversion problems

Hi all,

I am using the pg74.215.jdbc3.jar JDBC driver to connect to a PostgreSQL
7.4 database. I am getting the common error:

Invalid character data was found. This is most likely caused by stored
data containing characters that are invalid for the character set the
database was created in. The most common example of this is storing 8bit
data in a SQL_ASCII database.

I have read a lot online about how I need to convert my ASCII database
into UNICODE but I haven't been able to successfully do that. I have
dumped the DB and then added SET CLIENT_ENCODING TO 'UNICODE'; to the
top of the dump file and then tried to restore it to a UNICODE encoded
database. When I tried this only some of the tables (I assume the ones
without special characters) got imported, but many tables had zero rows.

Can someone please tell me how to convert an ASCII DB into a UNICODE DB
so hopefully the JDBC driver will actually work? I also read about a
patch for the JDBC driver. Where can I get this patch and does it work?

Thanks in advance for all your help,

Ron