how to solve launch_msg not connected

There may be a way to start in single-user mode, enter the correct command

and then restart from there into the normal GUI. However the info in your post

suggests two different products, as PowerBookG4 cannot run Mt Lion 10.8.5...

If your computer is a MacBook, running a more recent OS X than a PPC G4

can, then your topic could be moved by a Host into the correct ASC area.

•Start up in Single-User or Verbose Mode:

Mac OS X: How to start up in single-user or verbose mode - Apple Support

•7 Mac Startup Options Every OS X User Should Know:

http://www.tekrevue.com/tip/mac-startup-options/

Depending on how you arrived at the message, the path should be clear.

If you have a complete or duplicate backup of your computer content, a

different path could be taken to attempt to erase & install a new OS X.

More information may be needed; esp. if host should relocate your post.

Good luck & happy computing! 🙂