Install substruct ROR - Errors!

Hi all, I’m trying to install substruct on my local server on mac os x
snow
leopard.
I create the database on mysql, update all gems, update rails…but when
I
try to rake db:create I receive:

MacBook-Pro-di-Orazio:substruct_rel_1-3-1 Orazio$ rake db:create --trace
rake aborted!
uninitialized constant ActiveSupport::Dependencies::Mutex
/Library/Ruby/Gems/1.8/gems/rake-0.9.2/lib/rake/ext/module.rb:36:in
const_missing' /Users/Orazio/Desktop/substruct_rel_1-3-1/vendor/rails/activesupport/lib/active_support/dependencies.rb:55 /Library/Ruby/Site/1.8/rubygems/custom_require.rb:36:ingem_original_require’
/Library/Ruby/Site/1.8/rubygems/custom_require.rb:36:in require' /Users/Orazio/Desktop/substruct_rel_1-3-1/vendor/rails/activesupport/lib/active_support.rb:57 /Library/Ruby/Site/1.8/rubygems/custom_require.rb:36:ingem_original_require’
/Library/Ruby/Site/1.8/rubygems/custom_require.rb:36:in require' /Users/Orazio/Desktop/substruct_rel_1-3-1/vendor/rails/railties/lib/tasks/misc.rake:18 /Users/Orazio/Desktop/substruct_rel_1-3-1/vendor/rails/railties/lib/tasks/rails.rb:4:inload’
/Users/Orazio/Desktop/substruct_rel_1-3-1/vendor/rails/railties/lib/tasks/rails.rb:4
/Users/Orazio/Desktop/substruct_rel_1-3-1/vendor/rails/railties/lib/tasks/rails.rb:4:in
each' /Users/Orazio/Desktop/substruct_rel_1-3-1/vendor/rails/railties/lib/tasks/rails.rb:4 /Library/Ruby/Site/1.8/rubygems/custom_require.rb:36:ingem_original_require’
/Library/Ruby/Site/1.8/rubygems/custom_require.rb:36:in require' /Users/Orazio/Desktop/substruct_rel_1-3-1/Rakefile:12 /Library/Ruby/Gems/1.8/gems/rake-0.9.2/lib/rake/rake_module.rb:25:inload’
/Library/Ruby/Gems/1.8/gems/rake-0.9.2/lib/rake/rake_module.rb:25:in
load_rakefile' /Library/Ruby/Gems/1.8/gems/rake-0.9.2/lib/rake/application.rb:495:inraw_load_rakefile’
/Library/Ruby/Gems/1.8/gems/rake-0.9.2/lib/rake/application.rb:78:in
load_rakefile' /Library/Ruby/Gems/1.8/gems/rake-0.9.2/lib/rake/application.rb:129:instandard_exception_handling’
/Library/Ruby/Gems/1.8/gems/rake-0.9.2/lib/rake/application.rb:77:in
load_rakefile' /Library/Ruby/Gems/1.8/gems/rake-0.9.2/lib/rake/application.rb:61:inrun’
/Library/Ruby/Gems/1.8/gems/rake-0.9.2/lib/rake/application.rb:129:in
standard_exception_handling' /Library/Ruby/Gems/1.8/gems/rake-0.9.2/lib/rake/application.rb:59:inrun’
/Library/Ruby/Gems/1.8/gems/rake-0.9.2/bin/rake:32
/usr/bin/rake:19:in `load’
/usr/bin/rake:19
MacBook-Pro-di-Orazio:substruct_rel_1-3-1 Orazio$

Could anyone help me please?

Thank you so much!