WTF? I right click on a mod in the inventory, click on the attach mod tab, make sure the ranger has the skill necessary, point the pointer at the weapon to be modded, click, a box pops up and asks if I'm sure I want to mod this weapon, and EVERY SINGLE TIME I CLICK YES THE GAME CRASHES TO DESKTOP.

So..... can't use weapon mods in Wasteland 2???? What a joke. Guess it's a waste to take any weaponsmithing skill points.... despite the fact that you know, they're there and I specifically chose one character to put 4 skill points into it.

WTF?

I FOUND THE SOLUTION!!!g
Posting this here in case anyone else has the same problem.

I read it on the Steam forums... all I did was go into regedit, scroll down to inxile software (under HKEY USER etc etc)f and deleted the entire Wasteland 2 folder. Restarted the game and..... NOW IT DOES NOT CRASH WHEN I MOD A WEAPON

Have no idea why that happeend, but I'm glad it's fixed.