Make sure to use Java 64-bit !!! http://www.java.com/en/download/manual.jsp
I do recommend using MultiMC 5 (current version 0.3.5)
This should however work on most launchers although it might need to be done slightly different.
Install Minecraft 1.6.4 with Forge 18.104.22.1685 and run it once! MultiMC ---> Create new instance. Name it and select Minecraft version 1.6.4. Right-click the instance created and select 'edit mods'. Now a button on the right should show 'Install Forge'. Click it and select version 22.214.171.1245.
Download the modpack from the 'Permissions and download' topic.
Unpack the download using 7Zip or WinRar.
You will now have 2 folders called 'mods' and 'config'.
Browse your files for your Minecraft install/instance and replace both the 'mods' and 'config' folder with the ones you downloaded and unpacked. If the 'config' folder does not yet exist, just paste it in. MultiMC ---> Location of the folders in your instance to replace should look similar to this: E:\MultiMC\instances\Fun Paradise IV\minecraft\...
Before you run Minecraft again, make sure to give it enough memory and a big enough PermGen size. Extra Java Virtual Machine (JVM) parameters are optional though recommended. MultiMC ---> Right-click instance and select settings. Click the Java tab and set 'Minimum memory allocation' to 1024MB, 'Maximum memory allocation' to 2048MB - 4096MB max and 'PermGen' to 256MB - 512MB max. JVM parameters are optional but recommended.
Now run Minecraft and all should work just fine ;-)