Here is my code, like i say before i want to unwrap my connection but get an error

Code:
jdbcTemplate.execute(new ConnectionCallback() {
	            public Object doInConnection(Connection c) throws SQLException, DataAccessException {
					if (c.isWrapperFor(PGConnection.class))
					{
						c.unwrap(PGConnection.class);
					}
	            		
	                return null;
	            }
			});

Errors:

Code:
2009-06-02 11:19:56,619 ERROR [org.mortbay.log] [main] failed org.mortbay.jetty.servlet.Context@12943ac{/sync,null}
java.lang.AbstractMethodError: org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.isWrapperFor(Ljava/lang/Class;)Z
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:616)
	at org.springframework.jdbc.core.JdbcTemplate$CloseSuppressingInvocationHandler.invoke(JdbcTemplate.java:1283)
	at $Proxy0.isWrapperFor(Unknown Source)
	at org.jumpmind.symmetric.db.postgresql.PostgreSqlDbDialect$1.doInConnection(PostgreSqlDbDialect.java:63)
	at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:342)
I use:

java version "1.6.0_0"
OpenJDK Runtime Environment (IcedTea6 1.4.1) (6b14-1.4.1-0ubuntu10)
OpenJDK Client VM (build 14.0-b08, mixed mode, sharing)

and

postgresql-8.2-504.jdbc3.jar driver

Helpme

PD: excuses my bad english