[no subject]

For my project I can start from scratch or modify one of the existing
examples.  I am playing with both methods.  However, when I modify
GoesRetrieval.java and place

    import visad.data.netcdf.*;

near the top of GoesRetrieval.java and

    Plain plain = new Plain();

    FlatField netcdf_data = (FlatField) plain.open("equinox.nc");

just before 

    DisplayImplJ3D display1 = new DisplayImplJ3D("display1");

I get

    javac GoesRetrieval.java
    GoesRetrieval.java:311: JAVAC MESSAGE FILE IS BROKEN: 
key=javac.err.constructor.excemption, arguments=java.io.IOException, null, null
        FlatField netcdf_data = (FlatField) plain.open("equinox.nc");
                                                          ^
                                                          1 error

Can someone clue me into what this error means?