brew doctor errors

brew config:
HOMEBREW_VERSION: 0.9.5
ORIGIN: https://github.com/Homebrew/homebrew.git
HEAD: 43c301b5caf26d276950f5f9b9bc95c027bf235b
HOMEBREW_PREFIX: /usr/local
HOMEBREW_CELLAR: /usr/local/Cellar
CPU: 8-core 64-bit sandybridge
OS X: 10.9.3-x86_64
Xcode: 5.1.1 => /Volumes/500GB/Applications/Xcode.app/Contents/Developer
CLT: 5.1.0.0.1.1396320587
GCC-4.2: build 5666
Clang: 5.1 build 503
X11: 2.7.5 => /opt/X11
System Ruby: 2.0.0-451
Perl: /usr/bin/perl
Python: /usr/bin/python
Ruby: /Users/steve/.rvm/rubies/ruby-2.1.2/bin/ruby

brew doctor:
Error: invalid byte sequence in US-ASCII
Please report this bug:
    https://github.com/Homebrew/homebrew/wiki/troubleshooting
/usr/local/Library/Homebrew/cmd/doctor.rb:29:in `split'
/usr/local/Library/Homebrew/cmd/doctor.rb:29:in `get_mounts'
/usr/local/Library/Homebrew/cmd/doctor.rb:6:in `initialize'
/usr/local/Library/Homebrew/cmd/doctor.rb:718:in `new'
/usr/local/Library/Homebrew/cmd/doctor.rb:718:in `check_filesystem_case_sensitive'
/usr/local/Library/Homebrew/cmd/doctor.rb:1145:in `block in doctor'
/usr/local/Library/Homebrew/cmd/doctor.rb:1144:in `each'
/usr/local/Library/Homebrew/cmd/doctor.rb:1144:in `doctor'
/usr/local/Library/brew.rb:106:in `<main>'