error

gistfile1.txt

Warning: Your Xcode (4.2.1) is outdated
Please install Xcode 4.5.
Warning: It appears you have MacPorts or Fink installed.
Software installed with other package managers causes known problems for
Homebrew. If a formula fails to build, uninstall MacPorts/Fink and try again.
Error: undefined method `version' for nil:NilClass
Please report this bug:
    https://github.com/mxcl/homebrew/wiki/bug-fixing-checklist
/usr/local/Library/Homebrew/formula.rb:51:in `initialize'
/usr/local/Library/Homebrew/formula.rb:403:in `new'
/usr/local/Library/Homebrew/formula.rb:403:in `factory'
/usr/local/Library/Homebrew/formula.rb:447:in `block in expand_deps'
/usr/local/Library/Homebrew/formula.rb:446:in `map'
/usr/local/Library/Homebrew/formula.rb:446:in `expand_deps'
/usr/local/Library/Homebrew/formula.rb:442:in `recursive_deps'
/usr/local/Library/Homebrew/formula_installer.rb:46:in `check_install_sanity'
/usr/local/Library/Homebrew/formula_installer.rb:22:in `initialize'
/usr/local/Library/Homebrew/cmd/install.rb:78:in `new'
/usr/local/Library/Homebrew/cmd/install.rb:78:in `block in install_formulae'
/usr/local/Library/Homebrew/cmd/install.rb:76:in `each'
/usr/local/Library/Homebrew/cmd/install.rb:76:in `install_formulae'
/usr/local/Library/Homebrew/cmd/install.rb:21:in `install'
/usr/local/bin/brew:94:in `<main>'