$ ruby script/rails s thin
An exception occurred running script/rails
    dlopen(/Users/test/.rvm/gems/rbx-1.0.1-20100603/gems/libxml-ruby-1.1.3/ext/libxml/libxml_ruby.bundle, 10): Symbol not found: _assert
  Referenced from: /Users/test/.rvm/gems/rbx-1.0.1-20100603/gems/libxml-ruby-1.1.3/ext/libxml/libxml_ruby.bundle
  Expected in: flat namespace
 in /Users/test/.rvm/gems/rbx-1.0.1-20100603/gems/libxml-ruby-1.1.3/ext/libxml/libxml_ruby.bundle; dlopen(/Users/test/.rvm/gems/rbx-1.0.1-20100603/gems/libxml-ruby-1.1.3/ext/libxml/libxml_ruby.dylib, 10): image not found (SystemCallError)