Hi Frank - I'm not the right person to answer, but I don't see anyone else doing so. I've been running OCPN 2.3.0 (haven't loaded 2.3.1 yet) on Win7 ever since it came out, with no significant problems, so I can't really help you there. Is your Win7 up to date? I won't go into what other SW you've got loaded, as that's a REAL can of worms (but if you've got a geek friend, you should probably ask them to look for conflicts).
The biggest problem I've had connecting charting programs to GPSs is poor quality Serial-USB converters. NMEA-0182 is 0-5v, where RS232 Serial
is +/-9v, so they're NOT the same. A good quality USB-Serial converter will handle this discrepancy OK (although sometimes better when the computer is plugged in & charging) but poor quality ones only want to see RS232
signal levels, & don't know what to do with 0-5v NMEA
signal levels. Also, MSFT, in their infinite wisdom, changed the serial
port interface in Vista, so your drivers have to be Vista or Win7 drivers, not just XP drivers. FWIW, I've been using a 4-port Serial-USB made by KeySpan for several years. Cost more, but was guaranteed to work with my AIS
& it's been trouble free (touch wood).
As far as the charts, what they want you to do is to zoom in to wherever you've got chart coverage. If you're using the CM93 chart database, that should be the whole world, but you didn't say what charts you have. Remember that OCPN won't find your charts by itself - you have to tell it where they are on your hard drive. OCPN will show that black/outline "chart" when it doesn't think it has any other charts to show. Open the Toolbox & make sure your Charts tab includes a valid path to your charts (usually C:\CM93 for the CM93 chart database, otherwise wherever you've stashed your other charts).
Good luck, & sorry I couldn't be more help.