How to edit compilation-error-regexp-alist in .emacs file?

[Siegfried Heintze]

When I put the following in my .emacs fail, I get an error. This is probably
because the necessary modules have not been loaded yet.

How do I automatically execute these statements after the necessary modules
have been loaded?

(setcar (car compilation-error-regexp-alist) (concat "\\(\\[Error\\]
\\|\\[Fatal Error\\] \\)?"  (caar compilation-error-regexp-alist)))
  (setcdr (car compilation-error-regexp-alist) '(3 4 7))