I've tried to launch this a couple of times and reinstalled it in the past. Since I couldn't turn up anything through Google, could anyone help me with this coremod issue that won't even launch the client?
Are you referring to the FTB Client? Or the Modpack loading?
I'd always suggest you delete any and all files current relating to both and uninstalling and re installing java to start clean if you're getting that sort of error message. Also I've noted that many people claim issues with the latest Java 8.X, I'd recommend the latest version of Java 7 for use in Minecraft.[/QUOTE]