seems that neither the vanilla launcher nor forge b1245 downloads and installs the library "level":
org/apache/logging/log4j/Level
I'm at a complete loss here and from what I can see based diesieben07 response is that "we aren't supposed" to use launchers anymore, ie going back to the archaic way of doing things.
Gosh, I really hoping I'm taking that out of context. Please tell me that I am.