What is a sealed skill type?
Tried using the trait for it, but can't figure out what it does,
Thought it had to do with maxing out TP, but sadly no.

It blocks the use of that skill type. You should try to mouse over something like that and read the tooltip.

Well now that I fixed the problem, seeing how my friend had it on his usb drive and I didn't feel like walking to my cousin's for internet.
The version I had was cracked or a piss poor translated copy, cause everything but the tooltips worked. So I'm on the trail now so I can read everything though I have a limited time with it but hey.

Not 100% sure, but I believe it's a skill you can seal until the caster has met a certain requirement (such as a level or state condition, for example).