This is getting frustrating...but still entertaining. I tried the different Wilhelmshaven mods with mixed results. I finally tried loading v6 manually. It ran fine. Put in the Bridges add-on and got a crash. To fix that I had to remove the whole game and clean everything. Reloaded SH3, then GWX, then tried to run it that way. Crash. I deactivated and reactivated the 4-Gig patch. No luck. Then I made sure I had the GWX-Commander files installed. It's been so many years that I forgot all about that little wrinkle. Still no luck.
Then I remembered the Save-Game folder in My Documents. Deleted that and tried to start again, and got the message saying Commander can't function until the game has been run once. Good! That means it realizes it's a fresh install. Replayed the Navigation class, then tried a career start. All good so far.
Tomorrow I'm back to testing the Wilhelmshaven mods. I had planned on starting a career on New Years Day. Nine days later I haven't even started installing my favorite mods.
Maybe by next New Years...