This example you're trying is clearly not about Windows.
Check here:
http://docs.oracle.com/javase/7/docs/technotes/tools/windows/classpath.html
You need to use ;
as separator to say the least.
So you need something like this (this is all one line).
java -classpath c:\test\mycompanychecks.jar;c:\test\checkstyle-5.7-all.jar com.puppycrawl.tools.checkstyle.Main -c config.xml -r .