Did you download the default add-on? You need it to make the default work. You actually need 5 files, not 4. You need the 4 skintones and the add-on.

*hates dependent defaults with a passion*

To make a long story slightly shorter - The way a dependent default works is by having the face texture in the add-on and then pulling the body textures from the actual skintones. You have the face texture working but the body is wonky. What you need to do is to pull out ALL skintones from your Downloads folder, then throw in the add-on and the 4 Anva skintones. I suspect that there is something funky about either the add-on or another skintone in your downloads folder. Quite possibly, the add-on is attempting to pull body textures from two separate skintones and getting it's knickers in a knot because it's pulling the textures from two files. Out of curiosity - is it only crashing on aging to elder or on all birthdays but an elder birthday is all you've had in your game lately so that's all you know about?

Make sure that you don't accidentally have two copies of Anva's skintones in your Downloads. That could be what is causing the problem. Or get yourself a different default. Preferably not a dependent one.

It could be that you are using default replacement that don't have all the age groups. That's been known to happen. What default skins were you using for your sims?

Exactly what happens?
Are you sure you only have one of each default skin?
And you don't need the werewolf and plantsim skins if you don't have Pets or Seasons...