@Urckahjay Could you be more specific about what you're experiencing? If you're trying to use Isla Paridiso, you should know that the world is so poorly made that it's almost unplayable without some serious editing. (The gameplay features of the expansion pack work fine and translate well to other worlds, provided the water is deep enough for dive lots and for boats to navigate.)
What particular fixes have you tried? And what about your hardware? Depending on your computer's specs and which EPs you're trying to run, there are steps you should be taking to ensure that the game runs smoothly. For example, on newer graphics cards, the frame rates have to be capped, or the card can cause lagging and worse problems up to and including burning itself out completely.
If you could provide these details, someone would be able to give you more specific advice.
Wow... I had stopped playing my game for a few weeks and was so sad about it and even had thoughts of saving up money to purchase a better gaming computer with crazy RAM and a better graphics card. I finally decided to look it up and this worked like a charm! Thank you so much!!