@Tearz, I would try running the application from a different computer and see if it works for you. I suspect that there is some software that you might have running that is interfering, or the files were not extracted in a way that preserves the original file paths.
@Vandervecken, You're right, some of the tooltips are inaccurate. The items have stats determined by their base item, mods, and perm boosts and each stat has its own unique formula for scaling. I tried to match a lot of the formulas but many are still incorrect. There are only a few stats that I made certain are correct that include weapon damage, armour, and a few others. But anything else can be using the wrong formula.