I'm at the part where Vaklu sends a message to you to attack a sith base. When I arrive at the camp, A Cutscene triggers with Kelborn talking to you about the sith base. But what happens with me is Sith assassins spawn and Kelborn runs out to attack them, Skipping the cutscene. When he finishes I talk to him and he says "Are you ready to attack the base?". When I say yes I get transported to the area you should be, But I spawn as atton with no other party members and all the enemies are invisible. Help!

Sounds like the pre-Onderon Sith Assassins didn't spawn when they should and instead do now for you, breaking the cutscene.

 

TSLRCM fixes it, but that's a bit late for you now. Going back to the base and killing the spawn before the cutscene might work too, but that needs you to load a save from before getting the previous master.