fail to call edebug-defun

[Hongxu Chen <leftcopy.chx@gmail.com>]

Dear list,

  I need to take a deeper look at the execution of one of the elisp
  functions, and I run `edebug-defun' on it(let's suppose we are edebug
  on `find-file'), there is a confusing message about it:

  byte-code: Key sequence C-x C-a C-s starts with non-prefix key C-x C-a

  I know I should toggle-debug-on-error firstly, but that output quite a
  huge of message(although the *Backtrace* buffer only contains 7 lines
  with line wrapped) that I feel it's improper to paste here.

  Also I tried to start with `emacs -q', which works fine. However since
  I use quite a lot of packages from package.el and also does some
  customization, I feel that figuring out the root cause is a bit
  difficult for me.

  Have anybody else ever came across this problem? Or would you give me
  some advice?

  BTW, I am using a emacs from a Ubuntu PPA by Damien
  Cassou (https://launchpad.net/~cassou/+archive/emacs) and the result of
  `M-x emacs-version' is GNU Emacs 24.3.1 (x86_64-pc-linux-gnu, GTK+
  Version 3.4.2) of 2013-04-14 on chindi10, modified by Debian.

  Thanks!

-- 
Regards,
Hongxu Chen