Xcode MacRuby gem签名无效

我使用的是Xcode 4.5.2和MacRuby 0.12。 我需要使用电子表格gem，但当我尝试执行我的程序时，我一直存在“签名”问题：

/Library/Ruby/Gems/MacRuby/0.13/gems/ruby-ole-1.2.11.5/lib/ole/storage/base.rb:372:in `validate!': OLE2 signature is invalid (Ole::Storage::FormatError)
    from /Library/Ruby/Gems/MacRuby/0.13/gems/ruby-ole-1.2.11.5/lib/ole/storage/base.rb:364:in `initialize'
    from /Library/Ruby/Gems/MacRuby/0.13/gems/ruby-ole-1.2.11.5/lib/ole/storage/base.rb:105:in `load'
    from /Library/Ruby/Gems/MacRuby/0.13/gems/ruby-ole-1.2.11.5/lib/ole/storage/base.rb:72:in `initialize'
    from /Library/Ruby/Gems/MacRuby/0.13/gems/ruby-ole-1.2.11.5/lib/ole/storage/base.rb:78:in `open'
    from /Library/Ruby/Gems/MacRuby/0.13/gems/spreadsheet-0.7.4/lib/spreadsheet/excel/reader.rb:1179:in `setup'
    from /Library/Ruby/Gems/MacRuby/0.13/gems/spreadsheet-0.7.4/lib/spreadsheet/excel/reader.rb:121:in `read'
    from /Library/Ruby/Gems/MacRuby/0.13/gems/spreadsheet-0.7.4/lib/spreadsheet/excel/workbook.rb:32:in `open'
    from /Library/Ruby/Gems/MacRuby/0.13/gems/spreadsheet-0.7.4/lib/spreadsheet.rb:62:in `open'
    from /Library/Ruby/Gems/MacRuby/0.13/gems/spreadsheet-0.7.4/lib/spreadsheet.rb:68:in `open'

OLE gem与MacRuby兼容吗？我的选择是什么

谢谢你的帮助