1. make sure you have the latest Java 7u7 - for url look hereviewtopic.php?f=7&p=376853#p376842
- test it herehttp://java.com/en/download/testjava.jsp
2. make sure you're using the same bit version of Java and Ender - 32Bit + 32Bit or
64Bit + 64Bit
the run.bat has to point to the path of the right bit version of Java (32Bit - javaw.exe , 64Bit - java.exe)
there are different examples posted all over the forums...
3. ports TCP 1871 and UDP 1870 are needed - make sure your Firewall, Router or AV program aren't blocking them
(already said in post before yours...)
prolly it's the same reason why the default isn't finishing downloading - when default doesn't run properly any custom client won't aswell...