This is the error message I get whenever I try to start the game. I see the .dll files are there in the pso2 folder. I've tried to re-download dx9. I've also updated my gfx driver. The game has been working for the past few weeks. I just got this error about 6hrs since I've last played it.

Did you use the Weaker or MS Store. If it was the MS Store, make sure no updates are available. Otherwise, you have to run a file check in the game launcher.