Redmine

Description of the problem
Redmine runs for some time, but periodically hangs and stops to respond. I have one instance of Thin running. It doesn't write any error messages.

In Redmine's log I find this repeated strings after requests which brings system unresponding.

Completed 200 OK in 47ms (Views: 31.2ms | ActiveRecord: 0.0ms)
Connecting to database specified by database.yml
OpenIdAuthentication.store is nil. Using in-memory store.
Creating scope :active. Overwriting existing method User.active.
Creating scope :open. Overwriting existing method Version.open.
DEPRECATION WARNING: The InstanceMethods module inside ActiveSupport::Concern will be no longer included automatically. Please define instance methods directly in CollectiveIdea::Acts::NestedSet::Model instead. (called from include at c:/Ruby187/apps/redmine/lib/plugins/awesome_nested_set/lib/awesome_nested_set/awesome_nested_set.rb:58)
DEPRECATION WARNING: The InstanceMethods module inside ActiveSupport::Concern will be no longer included automatically. Please define instance methods directly in CollectiveIdea::Acts::NestedSet::Model instead. (called from include at c:/Ruby187/apps/redmine/lib/plugins/awesome_nested_set/lib/awesome_nested_set/awesome_nested_set.rb:58)
Creating scope :open. Overwriting existing method Issue.open.

More detailed log in attachment.

Environment
Operating system: Windows 2008 Server R2 Enterprise 64-bit
Database: MySQL Server 5.1.41
Web-server: Thin 1.3.1

Output of "rake about"

About your application's environment
Ruby version                       1.8.7 (i386-mingw32)
RubyGems version                   1.5.2
Rack version                       1.4
Rails version                      3.2.5
Active Record version              3.2.5
Action Pack version                3.2.5
Active Resource version            3.2.5
Action Mailer version              3.2.5
Active Support version             3.2.5

Middleware                         Rack::Cache,
                                   ActionDispatch::Static,
                                   Rack::Lock,
                                   #ActiveSupport::Cache::Strategy::LocalCache::Middleware:0x545bce0>,
                                   Rack::Runtime,
                                   Rack::MethodOverride,
                                   ActionDispatch::RequestId,
                                   Rails::Rack::Logger,
                                   ActionDispatch::ShowExceptions,
                                   ActionDispatch::DebugExceptions,
                                   ActionDispatch::RemoteIp,
                                   ActionDispatch::Callbacks,
                                   ActiveRecord::ConnectionAdapters::ConnectionManagement, 
                                   ActiveRecord::QueryCache,
                                   ActionDispatch::Cookies,
                                   ActionDispatch::Session::CookieStore,
                                   ActionDispatch::Flash,
                                   ActionDispatch::ParamsParser,
                                   ActionDispatch::Head,
                                   Rack::ConditionalGet,
                                   Rack::ETag,
                                   ActionDispatch::BestStandardsSupport,
                                   OpenIdAuthentication

Application root                   c:/Ruby187/apps/redmine
Environment                        production
Database adapter                   mysql
Database schema version            20120422150750