Error on Run App: Possible Path Error

My app run on DOS prompt (ruby), but not in Windows (rubyw) or Apache.

Using Aptana, when I go in (Run Configurations -> Environment) and
create a variable “path” with value “c:\ruby” it works.
But this directory is already set in my Windows PATH (My Computer ->
Properties -> Advanced -> System Variables).

Any suggestion?

It works in Netbeans too.
I’m using Windows XP SP2.

Thanks.

The Ruby version is 1.8.6 mswin32. This is necessary because I’m using
fireruby.