Glyph Gemspec validation error

rake gemspec:validate --trace

(in /Users/se/Downloads/glyph)
** Invoke gemspec:validate (first_time)
** Invoke version_required (first_time)
** Execute version_required
** Execute gemspec:validate
glyph.gemspec is invalid. See the backtrace for more details.
rake aborted!
undefined method `prerelease?' for nil:NilClass
/Users/se/.rvm/rubies/ruby-1.8.7-p299/lib/ruby/site_ruby/1.8/rubygems/specification.rb:1377:in `version='
/Users/se/.rvm/gems/ruby-1.8.7-p299@glyph/gems/jeweler-1.4.0/lib/jeweler/gemspec_helper.rb:56:in `join'
/Users/se/.rvm/gems/ruby-1.8.7-p299@glyph/gems/jeweler-1.4.0/lib/jeweler/gemspec_helper.rb:56:in `parse'
/Users/se/.rvm/gems/ruby-1.8.7-p299@glyph/gems/jeweler-1.4.0/lib/jeweler/commands/validate_gemspec.rb:12:in `run'
/Users/se/.rvm/gems/ruby-1.8.7-p299@glyph/gems/jeweler-1.4.0/lib/jeweler.rb:74:in `validate_gemspec'
/Users/se/.rvm/gems/ruby-1.8.7-p299@glyph/gems/jeweler-1.4.0/lib/jeweler/tasks.rb:86:in `define'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:636:in `call'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:636:in `execute'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:631:in `each'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:631:in `execute'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_chain'
/Users/se/.rvm/rubies/ruby-1.8.7-p299/lib/ruby/1.8/monitor.rb:242:in `synchronize'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:583:in `invoke'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:2029:in `each'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:2001:in `run'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/lib/rake.rb:1998:in `run'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/gems/rake-0.8.7/bin/rake:31
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/bin/rake:19:in `load'
/Users/se/.rvm/gems/ruby-1.8.7-p299@global/bin/rake:19