So I just downloaded the mincraft hack client/wrapper and it gave me the same problem a lot of ppl are having. I had the correct wrapper AND the 0.30 minecraft.jar, but it just wouldn't find it. This is a common problem of Win 7 and java, if it isnt configured like it's supposed to be, but there is a little workaround for that.
Edit your run.bat. right under "@echo off" put a new line:

cd %run.bat Path%

e.g.

cd C:\Users\YourName\Desktop\womclient-1.5.9

if it on your desktop inside the womclient-1.5.9 folder.
If it is somewhere else, like on a different partition than your OS, you need to put the letter in front. If I had it on D: (C: is my OS partition) i need to use:

D:
cd D:\womclient-1.5.9

its 2!! lines.
If it still doesnt work just put C:, D: or whatever infront just to be on the safe side, like in example 2.
next all you have to do is point the run.bat to your Java 32-bit installation with the explained command inside the run.bat e.g.

set JAVA6="C:\MyPath\bin\java.exe"

It worked for me, cause the win7 command prompt uses the system32-folder as the standard playe to run stuff. It would also work if you'd just entered the java-path and then used the command prompt to navigate to the client folder and then startet run.bat. It would then start inside the folder and it would find the subfolders lib, skin etc. without the above correction it would try to find the minecraft.jar inside system32/lib or whatever standard you got.

Quick example of my run.bat inside the client-folder on my desktop:

......
@echo off
cd C:\Users\Peter\Desktop\womclient-1.5.9
rem If you have a custom path to java, change auto below to
rem point to your java.exe file
rem eg:  set JAVA6="C:\MyPath\bin\java.exe"

set JAVA6="D:\Program Files (x86)\Java\jre6\bin\java.exe"
.....

I hope a lot of ppl can fix their problem with this. I made a new topic, cause I couldnt find an answer myself and there a re tons of topics stating the same problem, so for conveneice I opened a new topic.