invalid byte sequence in UTF-8

[Space Monkey]

Hi, I am following what was done in Rails Cast which uses Metrical.
http://railscasts.com/episodes/252-metrics-metrics-metrics
My local env is rails 3.1 and ruby 1.9.2

Metrical fails for a gem called syntax. Have any of you come across
such an error? How do I ignore this and proceed?


Analyzing: 100% |oooooooooooooooooooooooooooooooooooooooooo| Time:
00:00:03
/Users/ritvvijparrikh/.rvm/gems/ruby-1.9.2-p136@rails31/gems/
syntax-1.0.0/lib/syntax/lang/ruby.rb:85:in `===': invalid byte
sequence in UTF-8 (ArgumentError)
from /Users/ritvvijparrikh/.rvm/gems/ruby-1.9.2-p136@rails31/gems/
syntax-1.0.0/lib/syntax/lang/ruby.rb:85:in `step'