27:  How do I debug a .emacs file?

  Start Emacs with the "-debug-init" command-line option.  This enables the
  Emacs Lisp debugger before evaluating your .emacs file, and places you in
  the debugger if something goes wrong.  The top line in the trace-back
  buffer will be the error message, and the second or third line of that
  buffer will display the Lisp code from your .emacs file that caused the
  problem.

  You can also evaluate an individual function or argument to a function in
  your .emacs file by moving the cursor to the end of the function or
  argument and typing "C-x C-e" (M-x eval-last-sexp).

  Use "C-h v" (M-x describe-variable) to check the value of variables which
  you are trying to set or use.