I think you may need to go into a bit more detail as to what's going on.
I don't know much about XP and VX, 2k3 is more my area, but your events never gave out any equipment, and I'm not sure how that can be setup in the database. I'd imagine it's done seperately on each actor, and not class, in which case when you change their class it'll probably be unequipped if they can no longer use it. I'd suggest taking a look at my event-based character creation tutorial, as it may prove to be an easier way to do this(if it suits your style): http://www.rpgrevolution.com/forums/index....mp;#entry555218
Just replace races with classes and ignore the comments about race/class combinations(as you seem to only use gender and class) and it should work well.
As for the skills, what do you mean? That they keep their default class skills? If that's the case, give them a default class with no skills. Also, be sure that when you change their class you're replacing their previous skills with the new ones, not just adding them.
As I said, 2K3 is my area, so I'm not sure how that works in VX, but I hope this helps a little bit.