I've tried installing KIS and KAS through ckan and manually, yet everytime I start up the game all the EVA items can't be placed into any inventory slot. Other things such as winches and many other items can be put into the inventory, but not the EVA items including the screwdriver and the wrench. I have other mods installed but the problem is so specific that I can't imagine it's a problem with another mod. I posted on the Kerbal forum on Steam and another person did a fresh download of KIS & KAS and ended up having the same problem.

Into which inventory you're trying to put the items? EVA items from KIS cannot be placed into the stock inventory. You can only store them in the KIS inventory.