I've re-uploaded the zip file:
https://piratesahoy.bowengames.com/potc/Grey Roger/Night Craft.zip
The new version includes a few bug-fixes to the storyline, not all related to "Night Craft" - there was also a bug during the second main story mission whereby, if you had any passengers who weren't in your shore party when you went to see Tobias in Speightstown tavern, you lost them when you returned to Silehard and you got your officers and ship back. That's now fixed.
When the smuggler meets you in Port Royale to tell you about the quest, the gate is locked and fast travel is disabled so you can't skip the dialog. You now have the option to decline, in which case you don't get a questbook - yet. If you remember the meeting and go to see Desmond Ray Beltrop, he'll have a different introduction and then offer the quest anyway. Otherwise you can play the rest of the main story as if the quest never existed.
On your first mission for Desmond Ray Beltrop, the questbook now tells you that you need to take 300 sandal to Jean Maginot. If you have no sandal at all, you don't get the dialog from Jean Maginot to unload it. If you do have sandal but not enough, you get the dialog, you wait, and then he tells you that he was expecting 300. There's no time limit but you can't continue with the quest until you bring the full amount. You get a new questbook entry reminding you of how much you're supposed to deliver.
"France Trader_dialog.h" has a few small changes. Apart from some new lines at the end for when you didn't bring enough sandal, most of the changes are just rewording to make it sound better in English - for example, I believe "huckster" is relatively modern American slang so I changed it to "lease-monger", an old term meaning pretty much the same. But on line 91, there's now a preprocessed variable "#smonsieur#" which is filled in by "France Trader_dialog.c" so that he addresses you correctly if you're playing a female character.
@AkrimalS: in "Desmond Ray Beltrop_dialog.h", on line 228:What does "canal" mean here? Presumably he's not being compared to an inland waterway!