I have regenerated the files below. These are linked from http://www.unidata.ucar.edu/packages/netcdf-java/Please let me know if you have any further problems, although you might want to try using ftp directly.
ftp://ftp.unidata.ucar.edu/pub/netcdf-java/v2.1/netcdf.jar ftp://ftp.unidata.ucar.edu/pub/netcdf-java/v2.1/NetcdfJavaUserManual.pdf