Mac OSX Leopard + rails3 problems bad interpreter

hi , had rails 2 and then uninstall and install rails 3 but I have the
following problems when running rails new app

mac:~ Tinix$ rails new app
-bash: /usr/bin/rails:
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby: bad
interpreter: No such file or directory
mac:~ Tinix$

thanks for his help

Daniel T. Guzman

ruby 1.8.7 (2008-08-11 patchlevel 72) [i686-darwin9.0.0]

I solved my problem for this form
uninstall all ruby1.8.7
then with the

$sudo port install ruby19 rails3 and more
$sudo port install sqlite3

then when I running a new application on rubyonrails 3 all is ok!
but in the screen show the message

Could not find gem ‘sqlite3 (>= 0, runtime)’ in any of the gem sources
listed in your Gemfile.

then … running ‘bundle install’

the application es great with rails 3 !!!

see you