(DAMMIT INTERNET/CHROME FAIL, RAAAAGGGGEEEE!!!!!!)
(I'm not typing all that out again, so I'll just post the suggestions I had)
It seems to me to be a modloader issue, possibly, as it is throwing the exception when it initializes Modloader. Did you try to run MC right after you installed ModLoader? It helps identify problems if you run MC after installing each base mod, meaning Modloader, ModloaderMP, and Forge for most people. (Backing up, at the very least, the minecraft.jar after every step.)
Also, I've never heard of IZArc, link please? Maybe it's causing the problem, try another program? I'm using 7zip, and I've yet to have a problem with editing the minecraft.jar (It also doesn't ask to overwrite files, though, and autosaves when you exit the jar).