If I rename the folder, Vegas loads fine without my plugins. Vegas needs to tell me what plugin fails. I have at 104 different folders each from different manufacturers with multiple plugins within each. If I were to start selectively removing and putting back plugins till Vegas is happy it could potentially take hours to do.
Most DAWs will maintain a 'blacklist of plugins they can't handle; does Vegas not do this?
How long since you reinstalled your OS? I had weird problems with VP11 32bit which would just not load, even tho' the 64bit version loaded fine. I reinstalled the OS from a Acronis image and all works now.