java.sql.SQLException: 1 >= 1

I am getting the following exception from ResultSet.updateRow().

java.sql.SQLException: 1 >= 1
org.postgresql.jdbc2.AbstractJdbc2ResultSet.updateRow(AbstractJdbc2ResultSet.jav
a:1082)

I was wondering if anyone knows what it means.  I have not been able to
reproduce this is a simple example, so I'll descriibe what my code is doing.

I am running a coverage test for some code that I wrote that sits on top of
jdbc.  I create a table containing around 20 columns, one for each of the basic
jdbc data types.  I insert some data into the table, and then SELECT all the
columns (and rows) from the table.  I then update each of the columns of the
first row by calling the appropreate updateX( string, X ) method followed
immediately by an updateRow.

It looks something like this:

rs.updateInt( "integerCol", 1 );
rs.updateRow( );

rs.updateString( "stringCol", "fish" );
rs.updateRow( );

    .
    .
    .

Once each column has been updated I getX( string ) each of the columns to check
the data has been changed.  All this works without a problem.

Next I try to update the row again, this time using the updateX( int, X )
methods.  The exception is raised on the UpdateRow after I call updateX( int, X)
the first time.

I'm not sure if this exception means that I am doing something wrong or that
there is a bug in the jdbc.

Any clues to the cause of this expection would be appreciated.

Thanks

Darin