I could not get the knocker code at pinwheel export to work, the chart says the send shipment to dock code is, Ax4 - Bx2 - Ax2 but this wouldn't work, I found the correct code or one that works anyway on a walkthrough video, you have to add Ax2 - Bx2 to the original code, but why is this necessary, I cannot find any reference as to why the extra knocks should be added, is this yet another bug in what is easily the most buggy adventure game I have ever played?

So glad I've finished this game, I never want to see it again, hideous crap!

Thanks for that. I'm not sure what worked. I tried:
A4 - B2 - A2 - A2 - B2 and nothing happened.
Then I added another A2 and it worked.