Problems setting up a (free) Ada development environment

[Tim Rowe <spamtrap@tgrowe.plus.net>]

I'm trying to set up Ada on my Windows XP Pro system so I can learn Ada. 
  I've got the free version of GNAT, and would now like a development 
environment.

I've tried AdaGIDE, but when I run it all that happens is a shell 
console appears and disappears too fast for me to read what's in it. 
Running from a shell just gives the same result.

Ok, can't get AdaGIDE to work, so I try the AonixADT addon for Eclipse. 
To get that working I need to set up the "toolchain", but I can't find 
any explanation of what a "toolchain" is. The ADT tutorial says that 
"The Ada toolchain (ObjectAda, GNAT, etc.)  is located at the top level 
of the Ada installation - for example, C:/Program 
Files/Aonix/ObjectAda." So for GNAT, maybe it's at "C:\Program 
Files\gnat", which is where I've installed GNAT. Nope: "The specified 
location does not contain a valid GNAT installation". Maybe "C:\Program 
Files\gnat\2008"? Nope. "C:\Program Files\gnat\2008\bin"? Nope.

Could anybody help me to get either of those environments working, or 
point me to one that's easier to set up and use?

Thanks.