I've run into problems installing on OS X from source too. I found it
much easier to install MAMP and Locomotive.

http://locomotive.raaum.org/
http://www.mamp.info/en/home/

MAMP launches Apache and MySQL and Locomotive launches Ruby on Rails.
Both reside in the Applications folder with your other apps. The other
advantage is that you can save your projects in the Documents folder.
For me, that style has been easier to manage than the command-line.
While I'm comfortable with the command line, I'm not a pro. Using this
combination of applications, you'll be up and running within a half
hour.

Otherwise, this site has good notes on getting Ruby on Rails running
via the command line:

http://hivelogic.com/narrative/articles/ruby-rails-mongrel-mysql-osx

On Jun 7, 9:54 am, Mark <m... / acerbate.org> wrote:
> I have built Ruby from source, installed gems & rails on a MacBook
> pro.  I installed the source for a working Rails application in a
> directory /rails_apps.  I cd to the application directory under rails
> apps and in the terminal I enter:
>
> script/server
>
> Terminal responds:
> : No such file or directory
>
> sudo script/server provides the same response
> ls -la script/server returns:
> -rwxr-xr-x   1 pogo  admin  98 Nov 13  2006 script/server
>
> I have all of 2 weeks experience on a Mac, which probably explains the
> basic problem.  Can someone advise?