why is dm-core and dm-migrations missing?

gistfile1.txt

[jc@macbookpro ~/Merb/whitelabel_classifieds]# thor merb:gem:install
Beginning transaction
Installing extlib-0.9.9
Installing abstract-1.0.0
Installing erubis-2.6.2
Installing rake-0.8.3
Installing json_pure-1.1.3
Installing rspec-1.1.11
Installing rack-0.4.0
Installing mime-types-1.15
Installing thor-0.9.9
Installing merb-core-1.0.5
Installing ZenTest-3.11.0
Installing RubyInline-3.8.1
Installing sexp_processor-3.0.0
Installing ParseTree-3.0.2
Installing ruby2ruby-1.2.1
Installing merb-action-args-1.0.5
Installing merb-assets-1.0.5
Installing merb-cache-1.0.5
Installing merb-helpers-1.0.5
Installing mailfactory-1.4.0
Installing merb-mailer-1.0.5
Installing merb-slices-1.0.5
Installing merb-auth-core-1.0.5
Installing merb-auth-more-1.0.5
Installing merb-auth-slice-password-1.0.5
Installing merb-param-protection-1.0.5
Installing merb-exceptions-1.0.5
Installing haml-2.0.4
Installing merb-haml-1.0.5
Installing addressable-2.0.1
Installing data_objects-0.9.9
Installing dm-core-0.9.8
Installing dm-migrations-0.9.8
Installing merb_datamapper-1.0.5
Cannot find dm-core (= 0.9.8, runtime)
Installing dm-aggregates-0.9.8
Cannot find dm-migrations (= 0.9.8, runtime)
Installing dm-timestamps-0.9.8
Installing dm-types-0.9.8
Installing dm-validations-0.9.8
Installing dm-ar-finders-0.9.8
Installing do_mysql-0.9.9