Minecraft Forums

I downloaded the Curse app on my MacBook Pro to run modpacks but whenever I try to use one I get this script:

[23:01:15] [main/INFO]: Loading tweak class name cpw.mods.fml.common.launcher.FMLTweaker
[23:01:15] [main/ERROR]: Unable to launch
java.lang.ClassNotFoundException: cpw.mods.fml.common.launcher.FMLTweaker
at java.net.URLClassLoader$1.run(URLClassLoader.java:366) ~[?:1.7.0_79]
at java.net.URLClassLoader$1.run(URLClassLoader.java:355) ~[?:1.7.0_79]
at java.security.AccessController.doPrivileged(Native Method) ~[?:1.7.0_79]
at java.net.URLClassLoader.findClass(URLClassLoader.java:354) ~[?:1.7.0_79]
at java.lang.ClassLoader.loadClass(ClassLoader.java:425) ~[?:1.7.0_79]
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308) ~[?:1.7.0_79]
at java.lang.ClassLoader.loadClass(ClassLoader.java:358) ~[?:1.7.0_79]
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:106) ~[launchwrapper-1.12.jar:?]
at java.lang.ClassLoader.loadClass(ClassLoader.java:425) ~[?:1.7.0_79]
at java.lang.ClassLoader.loadClass(ClassLoader.java:358) ~[?:1.7.0_79]
at java.lang.Class.forName0(Native Method) ~[?:1.7.0_79]
at java.lang.Class.forName(Class.java:274) ~[?:1.7.0_79]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:98) [launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]

I've tried launching using different packs and I always get the same script back. I'm new to the whole process and I'm not sure what to do next. I also tried launching with different java updates and none I've tried have worked. I'm currently using Java 7.