Help with building source jar

I am trying to use one of my mods as a core mod, an API to my other mods if you will. Now I coded both, the core mod and the one trying to use it as an API. I am trying to make a notification system, here is the code

[embed=425,349] @SubscribeEvent

public void onGuiOverlay(RenderGameOverlayEvent event) {

if (Minecraft.getMinecraft().currentScreen == null || !(Minecraft.getMinecraft().currentScreen instanceof GuiViewNotifications)) {

for (Object not : mod.getNotifications().toArray()) {

((Notification) not).draw(Minecraft.getMinecraft(), event.resolution.getScaledWidth(),

event.resolution.getScaledHeight(), event.mouseX, event.mouseY);

}

}

}[/embed]

Which I can PROMISE you is only loaded client side. But when I use it as an API I get an error at the Minecraft.getMinecraft().currentScreen, which is "NoSuchMethodException". So what is the issue? Also this is when I run the mod in eclipse, the main mod with the core mod being in the libs folder. It only calls this error on the method when I am using it in the other mod as a dependency in the libs, it works fine when I run Minecraft with eclipse for just the core mod alone.