I will try and help u out as much as possible.
1) Item Editor: grab the 3.3 Beta version off the 3.2 release post.
2) MySQL (possible faulty): check out this
post for how to setup a server. Should also explain how to setup MySQL.
3) PEQ Velious: should just have to source it in.
Also make sure you have the latest item database from
here. Hope that helps you along.