Hey, I had the same sort of error, but in my standalone Minecraft. I was able to get it to work by deleting the redpower file in my User/Library/ApplicationSupport/minecraft, or in your case User/Library/ApplicationSupport/techniclauncher. Idk if technic comes with a preconfigured redpower config, if it does, then try to backup your saves and delete everything. Idk if this made much sense but make sure to make backups.