Welcome Aboard Ronnie67!
I did not have your particular error using steam but my error was SH3 would not load at all nor would I get an error message. I found that it was running in the background and I had to stop it using task manager. Then the game would run. I used SH3 Commander to run the game after that episode without having any more failure to load errors. My Nvidia 8800 gt card also caused some errors with GWX until I
disabled anti-aliasing. SH3 commander can be found here:
http://www.subsim.com/radioroom/down...o=file&id=2923
I have also had to re-install the game several times due to crashes from mods I used. If you have to re-install make sure you completely delete the SH3 game folder from the steamapps folder. I made a backup copy of the game after I downloaded it from steam.
If you do an advance search of the forum for "Steam Version" and select the Silent Hunter III forum only. There are a lot of threads in reference to steam and SH3.
Good Luck