Exception when inserting boolean values into BIT columns

I have a problem with BIT datatypes accessed via JDBC. When I try to
insert a Boolean value via a PreparedStatement, I get the following
exception (using the newest JDBC driver, postgresql-8.0-311.jdbc3.jar,
against a 8.0.1 database on Windows, Java is 1.5.0_1):

Exception in thread "main" java.sql.SQLException: ERROR: column "isok"
is of type bit but expression is of type boolean
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:1471)
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1256)
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:175)
at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:389)
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:330)
at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:321)
at org.apache.commons.dbcp.DelegatingPreparedStatement.execute(DelegatingPreparedStatement.java:168)
at Main.main(Main.java:27)

This is the corresponding test code:

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.Statement;
import java.sql.Types;
import org.apache.commons.dbcp.BasicDataSource;

public class Main
{
public static void main(String[] args) throws Exception
{
BasicDataSource dataSource = new BasicDataSource();

dataSource.setDriverClassName("org.postgresql.Driver");
dataSource.setUrl("jdbc:postgresql://localhost/test");
dataSource.setUsername("postgres");
dataSource.setPassword("root123");

Connection connection = dataSource.getConnection();
Statement statement = connection.createStatement();

statement.execute("CREATE TABLE Test(id SERIAL, isOk BIT);");
statement.close();

PreparedStatement prepStatement =
connection.prepareStatement("INSERT INTO Test (isOk) VALUES (?);");

prepStatement.setObject(1, Boolean.TRUE, Types.BIT);
prepStatement.execute();
prepStatement.close();
connection.close();
}
}

(btw, the same exception is generated when using setBoolean instead of
setObject.)

Any ideas ?

regards,
Tom