If you have trouble with the latest version of the installer you may have more success if using Java 8.
Ill be looking into this and will have a fix soon.
Also, for those downloading manually or if the installer refuses to download it, the link to Stealthware Core is below. Stealthware Core 2.0
UPDATE: The installer is now fixed and should run on any version of Java.
The new 2.0 version of Server Command GUI is now available.
It has an amazing new interface and is fully extendible with mod support.
See the article for details.
Since 1.6.4 released the old Server Commands GUI no longer works. Luckily i have a brand new version almost ready to go.
See the forum thread to get all the details and try it for yourself.
The final release will be in a few weeks when ive had chance to fix the bugs and tweak a few things.
The all new Stealthware Mod Installer is ready to go! Try it out pack.stealthware.co.uk.
All the mods are now compatible with Minecraft 1.5.
Plus some significant changes to MoreMeat allow it to work better with other mods.