Command failed with status (127)

I am trying to run units tests on an exercise for a Rails class I am
taking and encountered this error message:

rake aborted!
Command failed with status (127): [C:/jruby-1.5.3/bin/jruby.exe
-I"lib;test" …
]

Does this means the jdbc adapter does not work on my environment
(Windows XP SP3)? Is this a jruby bug? Please advise. Thanks!

Here is the full trace:

C:\Documents and Settings\macrogeo\My
Documents\JP-RR\rails_testing\solutions.ne
tbeans6.9\exercise0\rubyweblog>jruby -S rake test:units --trace
(in C:/Documents and Settings/macrogeo/My
Documents/JP-RR/rails_testing/solution
s.netbeans6.9/exercise0/rubyweblog)
** Invoke test:units (first_time)
** Invoke db:test:prepare (first_time)
** Invoke db:abort_if_pending_migrations (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute db:abort_if_pending_migrations
** Execute db:test:prepare
** Invoke db:test:load (first_time)
** Invoke db:test:purge (first_time)
** Invoke environment
** Execute db:test:purge
** Execute db:test:load
** Invoke db:schema:load (first_time)
** Invoke environment
** Execute db:schema:load
** Execute test:units
C:/jruby-1.5.3/bin/jruby.exe -I"lib;test"
“C:/jruby-1.5.3/lib/ruby/gems/1.8/gems
/rake-0.8.7/lib/rake/rake_test_loader.rb” “test/unit/comment_test.rb”
“test/unit
/post_test.rb” “test/unit/helpers/posts_helper_test.rb”
rake aborted!
Command failed with status (127): [C:/jruby-1.5.3/bin/jruby.exe
-I"lib;test" …
]
C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:995:in sh' C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1010:incall’
C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1010:in
sh' C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1098:insh’
C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1029:in
ruby' C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1098:inruby’
C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake/testtask.rb:117:in
de fine' C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1112:inverbose’
C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake/testtask.rb:102:in
de fine' C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:incall’
C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in
execute' C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:ineach’
C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in
execute' C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:ininvoke_with
_call_chain’
C:/jruby-1.5.3/lib/ruby/1.8/monitor.rb:191:in mon_synchronize' C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:ininvoke_with
_call_chain’
C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in
invoke' C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:ininvoke_tas
k’
C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in
`top_level’

C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in
each' C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:intop_level’

C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in
standard_e xception_handling' C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:intop_level’

C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in
run' C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:instandard_e
xception_handling’
C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in
run' C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/bin/rake:31 C:/jruby-1.5.3/lib/ruby/gems/1.8/gems/rake-0.8.7/bin/rake:19:inload’
C:/jruby-1.5.3/bin/rake:19