Trying to convert from .xml to .srt throws exception

[intelligence]

Trying to convert a sub from xml to srt and get below..

subtitle_it milfay.xml milfay.srt
Working on file milfay.xml...
/Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/subtime.rb:9:in `initialize': unhandled exception
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/subline.rb:21:in `new'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/subline.rb:21:in `block in filter'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/subline.rb:20:in `map'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/subline.rb:20:in `filter'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/subline.rb:12:in `initialize'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/formats/xml.rb:33:in `new'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/formats/xml.rb:33:in `block in parse_xml'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/nokogiri-1.6.7.1/lib/nokogiri/xml/node_set.rb:187:in `block in each'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/nokogiri-1.6.7.1/lib/nokogiri/xml/node_set.rb:186:in `upto'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/nokogiri-1.6.7.1/lib/nokogiri/xml/node_set.rb:186:in `each'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/formats/xml.rb:30:in `parse_xml'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/subtitle.rb:73:in `parse_lines!'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/subtitle.rb:69:in `parse_dump'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/subtitle.rb:40:in `initialize'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/bin.rb:9:in `new'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/bin.rb:9:in `run!'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/lib/subtitle_it/bin.rb:102:in `run!'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/gems/subtitle_it-2.0.1/bin/subtitle_it:68:in `<top (required)>'
    from /Users/x/.rvm/rubies/ruby-2.2.1/bin/subtitle_it:23:in `load'
    from /Users/x/.rvm/rubies/ruby-2.2.1/bin/subtitle_it:23:in `<main>'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/bin/ruby_executable_hooks:15:in `eval'
    from /Users/x/.rvm/gems/ruby-2.2.1@global/bin/ruby_executable_hooks:15:in `<main>'