RuntimeError: Command C:/<ruby>/bin/ruby.exe -I"C:/<ruby>/lib/<ruby>/gems/1.8/gems/rspec-1.2.7/lib"  "C:/<ruby>/lib/<ruby>/gems/1.8/gems/rspec-1.2.7/bin/spec" "another_spec.rb" "my_spec.rb" --require 'teamcity/spec/runner/formatter/teamcity/formatter' --format Spec::Runner::Formatter::TeamcityFormatter:matrix failed

Stacktrace:
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rspec-1.2.7/lib/spec/rake/spectask.rb:177:in `define'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1112:in `verbose'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rspec-1.2.7/lib/spec/rake/spectask.rb:153:in `define'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `call'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `standard_execute'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `each'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `standard_execute'
C:/TeamCity/buildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:260:in `execute'
C:/TeamCity/buildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:90:in `target_exception_handling'
C:/TeamCity/buildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:266:in `execute'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_chain'
C:/<ruby>/lib/<ruby>/1.8/monitor.rb:242:in `synchronize'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:607:in `invoke_prerequisites'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:604:in `each'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:604:in `invoke_prerequisites'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:596:in `invoke_with_call_chain'
C:/<ruby>/lib/<ruby>/1.8/monitor.rb:242:in `synchronize'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in `standard_invoke_with_call_chain'
C:/TeamCity/buildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:235:in `invoke'
C:/TeamCity/buildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:90:in `target_exception_handling'
C:/TeamCity/buildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:234:in `invoke'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
C:/TeamCity/buildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:311:in `standard_exception_handling'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run'
C:/TeamCity/buildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:311:in `standard_exception_handling'
C:/<ruby>/lib/<ruby>/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run'
C:/TeamCity/buildAgent/plugins/rake-runner/lib/rb/runner/rake_ext.rb:179:in `run'
C:/TeamCity/buildAgent/plugins/rake-runner/lib/rb/runner/rakerunner.rb:40