I took a quick look at your roster. You seem to have good PF's and wingmen, but you only have one PG (and from his salary I would guess he's average, and he's quite tall for a PG) and your centers are all under 4k. Like I said I don't know in detail your players' skills, but maybe playing Full Court Press on D isn't working. FCP gets you a lot of steals, but against teams that have good handling it just leads to a lot of easy baskets. And it also tires your players faster I guess, you need a lot of stamina. Have you considered switching to one of the other defensive tactics? I usually play 2-3 zone to try and have an advantage on the rebounds, but I always do a background check on my opponents. If they shoot at a good % from the outside I switch tactics, otherwise 2-3 zone is just inviting them to shoot. So my point is, try and find a tactic that suits your players, especially on D, but be ready to adjust depending on your next opponent.
Good luck ;)