error at new rails app creation

In cmd prompt, I just tried to new rails app using,
~/documents>rails new app_name
It throws an error as,
Gem::InstallError: The 'json' native gem requires installed build tools.

In cmd prompt, I just tried to new rails app using,
~/documents>rails new app_name
It throws an error as,
Gem::InstallError: The 'json' native gem requires installed build tools.

You have some build tools missing. Without knowing which OS you are
using and how you installed ruby and rails it is difficult to say
more. I recommend using rvm for installing ruby and rails. rbenv may
be a good alternative but I have no experience of that.

Colin

I've Windows7, Ruby 1.9.3 and Rails 3.2.6

Please quote the previous message and insert your reply inline at
appropriate points in previous message so it is easier to follow the
thread. This is a mailing list not a forum (though you may be
accessing it via a forum-like interface.

I've Windows7, Ruby 1.9.3 and Rails 3.2.6

In that case my advice is don't bother. Switch to a linux
distribution such as Ubuntu, or use a Mac. In the long run life will
be much simpler. You can dual boot ubuntu or use a VM. However I
believe some have had success developing in windows so someone else
may be able to help.

Colin