The support files for this program needs to upgraded to work with Matlab 2009a. You will need to get the latest version of the mexcdf package, which is available at sourceforge, at http://mexcdf.sourceforge.net/downloads/R2008a.html. Just replace the files in the mexnc and netcdf subdirectories with the new files in the subdirectories with the same names in the mexcdf package. Matlab now provides native support for netcdf files, so there is no need to generate dll or mex files. Everything will work just fine.