Error when attempting to call Connection.createArrayOf() method

I am trying create an array of text to pass to a postgreSQL function
and I am getting the following error
"java.lang.AbstractMethodError:
org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.createArrayOf(Ljava/lang/String;[Ljava/lang/Object;)Ljava/sql/Array;"

I am using JDBC driver (postgresql-8.4-701.jdbc4.jar) for postgreSQL
and commons-dbcp-1.2.2.jar for connection pooling.

My code like like this.

String[] _input_values={"one","two"};
conn.createArrayOf("text",_input_values)

Allan.