If you get the following errors when using Rails:

/usr/lib/ruby/1.8/xmlsimple.rb:275: warning: already initialized constant KNOWN_OPTIONS
/usr/lib/ruby/1.8/xmlsimple.rb:280: warning: already initialized constant DEF_KEY_ATTRIBUTES
/usr/lib/ruby/1.8/xmlsimple.rb:281: warning: already initialized constant DEF_ROOT_NAME
/usr/lib/ruby/1.8/xmlsimple.rb:282: warning: already initialized constant DEF_CONTENT_KEY
/usr/lib/ruby/1.8/xmlsimple.rb:283: warning: already initialized constant DEF_XML_DECLARATION
/usr/lib/ruby/1.8/xmlsimple.rb:284: warning: already initialized constant DEF_ANONYMOUS_TAG
/usr/lib/ruby/1.8/xmlsimple.rb:285: warning: already initialized constant DEF_FORCE_ARRAY
/usr/lib/ruby/1.8/xmlsimple.rb:286: warning: already initialized constant DEF_INDENTATION
/usr/lib/ruby/1.8/xmlsimple.rb:287: warning: already initialized constant DEF_KEY_TO_SYMBOL

then execute the following script to remove the warnings:

#!/bin/sh
cd /usr/lib/ruby/1.8
if [ -h lib/xmlsimple.rb ]; then
mv lib/xmlsimple.rb lib/xmlsimple.rb.old
mv xmlsimple.rb lib/.
cat > xmlsimple.rb <<!
require 'lib/xmlsimple.rb'
!
else
echo `pwd`/lib/xmlsimple.rb is not a link. Exiting.
fi