Descriptor Index not Valid.

["Mangavalli, Ramanujam" <RamM@xxxxxxxxxxx>]

I am getting a "java.sql.SQLException: Descriptor index not valid." Error.
Anyone have any suggestions how to get rid of this?
I am trying to extend the AbstractTableModel and write a custom table model
and display a JTable that displays data from the iSeries 400. I am getting
this error when the following is executed:

validRow = getResultSet().next()

if (validRow)

// store row in the dummy row vector.
//
...
...
...

there are two rows in the table. Both of them are retrieved. When I try to
get the third row, I get the Descriptor Index Not Valid error.
I am using Eclipse and imported(actually I had to copy the class files into
the workspace) the ET400 classes.

Thanks in advance.