Problem with 7.4 driver

I just upgraded to 7.4 and I'm getting this when I try to use the jdbc
driver:


Exception in thread "main" java.lang.NoSuchMethodError:
org.postgresql.core.StartupPacket.writeTo(Lorg/postgresql/core/PGStream;)V
         at
org.postgresql.jdbc1.AbstractJdbc1Connection.openConnectionV2(AbstractJdbc1Connection.java:585)
         at
org.postgresql.jdbc1.AbstractJdbc1Connection.openConnection(AbstractJdbc1Connection.java:215)
         at org.postgresql.Driver.connect(Driver.java:122)
         at java.sql.DriverManager.getConnection(DriverManager.java:512)
         at java.sql.DriverManager.getConnection(DriverManager.java:171)

But I checked and that method does indeed exist.  I built the driver
twice.  Any idea what the problem is?

The line that throws the Error is:

            new StartupPacket(PGProtocolVersionMajor,
                              PGProtocolVersionMinor,
                              PG_USER,
                              database).writeTo(pgStream);