Modloader 1.2.5 help?

ok, so I've been using mods for a while now, and I decided to use some old 1.2.5 mods, like zeppelin mod. I downloaded zeppelin mod, optifine, MC forge, Buildcraft, and Balkons weapons. I know most of these are up to date, but I got some old versions because I wanted to use them with zeppelin mod. I then read that Buildcraft required modloader as well as MC forge, so I got a 1.2.5 version of that as well. I tried two different builds (both from risugami's mods on MC forums) The first wouldn't even show up on magic launcher and both versions would cause a crash and corrupt jar file if I installed it manually, even without other mods. I've used modloader 1.2.5 before and have no idea why it isn't working now, any help?

Yes I did delete Metainf
I used Minecraft Version Changer to change my MC version to 1.2.5 from 1.5
Modloader would crash my game even with no mods installed

Oh and GamerGeekJake, thanks for the reply, but just using forge was the first thing I tried, it crashed my game, and that's why I looked at the website for installation instructions and found that I needed Modloader.

If your look at the Buildcraft website you will see that the older versions of Buildcraft required Forge and Modloader
Here is a screenshot of the page (If I can find out how to add pictures