grails emacs mode - "Cannot open load file" "project-mode" - grails

Question

I am trying to use emacs for grails development. Tried on grails-emacs-mode
There are emacs and emacs23 on my ubuntu 12.04.
prayag#prayag:~$ ls -l /usr/share/emacs[tab][tab]
emacs/ emacs23/
As the grails-emacs-mode suggests, I copied grails-mode.el and primary.org files to my emacs23/site-list
prayag#prayag:~$ ls -l /usr/share/emacs23/site-lisp/
total 32
-rw-r--r-- 1 root root 3013 Nov 17 00:39 debian-startup.elc
drwxr-xr-x 2 root root 4096 Nov 17 00:39 dictionaries-common
-rw-r--r-- 1 root root 18205 Feb 14 01:11 grails-mode.el
-rw-r--r-- 1 root root 0 Feb 14 01:11 primary.org
-rw-r--r-- 1 root root 106 Sep 22 01:16 subdirs.el
Then, created init.el inside .emacs.d as there exists no .emacs file in home directory. The init.el conatains
(require 'grails-mode)
(setq grails-mode t)
(setq project-mode t)
(add-to-list 'auto-mode-alist '("\.gsp$" . nxml-mode)) ; Use whatever mode you want for views.
(project-load-all) ; Loads all saved projects. Recommended, but not required.
now, opening emacs23 doesn't show any grails in the menubar.
I also tried
M-x
load-file .emacs.d/init.el
which throws
Warning (initialization): An error occurred while loading `/home/prayag/.emacs.d/init.el':
File error: Cannot open load file, project-mode
To ensure normal operation, you should investigate and remove the
cause of the error in your initialization file. Start Emacs with
the `--debug-init' option to view a complete error backtrace.
On starting emacs23 --debug-init, following error is thrown.
Debugger entered--Lisp error: (file-error "Cannot open load file" "project-mode")
require(project-mode)
eval-buffer(#<buffer *load*<2>> nil "/usr/share/emacs/23.3/site-lisp/grails-mode.el" nil t) ; Reading at buffer position 422
load-with-code-conversion("/usr/share/emacs/23.3/site-lisp/grails-mode.el" "/usr/share/emacs/23.3/site-lisp/grails-mode.el" nil t)
require(grails-mode)
eval-buffer(#<buffer *load*> nil "/home/prayag/.emacs.d/init.el" nil t) ; Reading at buffer position 23
load-with-code-conversion("/home/prayag/.emacs.d/init.el" "/home/prayag/.emacs.d/init.el" t t)
load("/home/prayag/.emacs.d/init" t t)
#[nil "\205\264

Answer 1

grails-mode requires project-mode as mentioned on the emacs-grails-mode page. So, you'll also need to install project-mode.
Also grab the remaining groovy packages(all but grails-mode) from here.
emacs-grails-mode-ext is a modest contribution to grails-mode allowing you to run Grails commands directly from emacs. For a given project(project-mode), you can run Grails commands such as create-domain-class, create-service, etc.
I also use the function ido-find-file-in-tag-files from here, I bind it to C-x C-M-f .
Simple guide with emacs-grails-mode:
Create a project from the command line or eshell -> grails create-app yourapp
Using dired, go to your Grails project folder
M-x project-new -> to create a new project(project-mode)
M-x project-save -> Save the project
M-x project-load-and-select -> Your project-name as argument
There's also a Grails menu if you use the menubar
You could also use my current emacs setup here, if you have emacs24 installed. I believe that it's available for Ubuntu 12.04, but I'm not sure. I usually build emacs from source on OSX or I use emacs-snapshot in Ubuntu.
Hope this helps.

Answer 2

I don't know Grail-mode at all. I've just clicked your link, and they state that project-mode is a dependency:
Dependencies:
project-mode is the only dependency.
As a consequence you will also have to install it. Link to the Emacs project code.
I am hoping for you this project does not have additional dependencies...
As a side note: later, try to install the last emacs (v24) which embeds a very convenient way to deal with package installation and dealing with packages dependencies. I've just check it out, it is present on an alternative (but very know) repository: Marmalade-repo.org.