There is no problem with the CA catalog or the plugin as far as I can tell, so what comes to mind is:
a) You really didn't have internet
b) Windows is blocking access to the place where your charts
are (It is a very bad practice to place data into a program files folder and the OS can be set to "protect" you from having programs writing there)
c) The catalog was temporarily unavailable from NOAA (now resolved as I can't see any problem)
Try moving your charts
to some more reasonable location, like the default one the plugin suggests you when you add the catalog and make sure that the user you use to run OpenCPN
has write access there.