To use the Fast Ruby Debugger with NetBeans you need to install the ruby-debug-ide gem (If you haven't installed Ruby, do that first). However, since that gem (among many others) uses native C extensions, gcc needs to be installed first:

bleonard@opensolaris:~$ pfexec pkg install SUNWgcc
DOWNLOAD                                    PKGS       FILES     XFER (MB)
Completed                                    5/5   2078/2078 114.44/114.44

PHASE                                        ACTIONS
Removal Phase                                    2/2
Update Phase                                   23/23
Install Phase                              2482/2482
bleonard@opensolaris:~$ 

There's a bug where the rbconfig.rb file contains bogus paths (6705310) causing native extensions to fail to build. Prashant Srinivasan provides an updated rbconfig.rb via his blog, Where's my Ruby. Run:

bleonard@opensolaris:~$ cd /usr/ruby/1.8/lib/ruby/1.8/i386-solaris2.11/
bleonard@opensolaris:/usr/ruby/1.8/lib/ruby/1.8/i386-solaris2.11$ pfexec mv rbconfig.rb rbconfig.rb.orig
bleonard@opensolaris:/usr/ruby/1.8/lib/ruby/1.8/i386-solaris2.11$ pfexec wget http://blogs.sun.com/prashant/resource/gcc/rbconfig.rb
--17:54:04--  http://blogs.sun.com/prashant/resource/gcc/rbconfig.rb
           => `rbconfig.rb'
Resolving blogs.sun.com... 72.5.124.56
Connecting to blogs.sun.com|72.5.124.56|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 6,864 (6.7K) [text/plain]

100%[==========================================================================================================================>] 6,864         --.--K/s             

17:54:04 (52.83 KB/s) - `rbconfig.rb' saved [6864/6864]

bleonard@opensolaris:/usr/ruby/1.8/lib/ruby/1.8/i386-solaris2.11$

Now the ruby-debug-ide gem should build successfully. However, NetBeans 6.1 does not work with the lastest version of ruby-debug-ide (0.2.0), so we have to explicity install version 0.1.0.

bleonard@opensolaris:~$ pfexec gem install ruby-debug-ide -v 0.1.10 --include-dependencies
Select which gem to install for your platform (i386-solaris2.11)
 1. ruby-debug-base 0.10.0 (mswin32)
 2. ruby-debug-base 0.10.0 (ruby)
 3. Skip this gem
 4. Cancel installation
> 2
Building native extensions.  This could take a while...
Successfully installed ruby-debug-ide-0.1.10
Successfully installed ruby-debug-base-0.10.0
Installing ri documentation for ruby-debug-base-0.10.0...
Installing RDoc documentation for ruby-debug-base-0.10.0...
bleonard@opensolaris:~$ 

Now start NetBeans 6.1 and add the Ruby platform. Select Tools > Ruby Platforms to open the Ruby Platforms Manager:



If you haven't already added Ruby as a platform, click the Audodetect Platforms button:

You'll see that NetBeans has detected the that Fast Debugger is already installed. Happy debugging.