I seems to have 'nil' as one of the members of the list
'load-path'. Being this the case package.el breaks while defining a
custom variable. Attached is the patch for this.

package.el: Fix to check 'nil' member in load-path.

* lisp/emacs-lisp/package.el (package-directory-list) : Ignore 'nil'
member from load-path if exists.

Thanks and Regards
Noorul