I made my own CMP with Voltz as well, and it works on my server I think and for just playing on solo worlds, but for some reason when I try to connect to the server, the screen says it's logging in then just has a "Done" button at the bottom. Am I doing something wrong or could it just be my computer? I have not tested it on other user yet.
I have the whole Voltz Package plus Thaumcraft 3, Computercraft v1.5, Balkons Weapon Mod, Iron Chests Mod, and Redpower.
It does not state that I don't have certain mods or the wrong version of the mods.
I also have the Voltz Server pack installed for myself as well.