When the update first came out, I could not sail on one of my systems.. further potco updates since have resolved that problem.
When the udpate first came out, and my system wouldnt sail, I immediately attempted driver updates, they did not help. After potco updated again... it still did not work, UNTIL I restored back to my previous (older) set of drivers, after I did that, it worked fine again.
IF your friends tried driver updates or anything after they started having problems, they might try going back to thier original configuration (ie system restore) that last worked with the game.
I have experienced slower screen loading, Tp'ing not as responsive. I've had to click on my map 3-5 times to get it to tp. I've also had the weapon sticking, however i've had it happen with my dagger, and cutlass, as well as my pistol. Any lag issues I have had, were during heavy sailing battles, but this wasnt particularly... 'new'.
Zeppers lvl40
http://pirates.teamofx.us