Looks like you need to install the module Net::IP. It also looks like you are on windows so I am assuming you are using ActiveState Perl so you will want to use PPM to install Net::IP. I haven't used ActiveState or PPM in a while, so look here: http://docs.activestate.com/activeperl/5.10/faq/ActivePerl-faq2.html
Except that Net::IP won't actually do what the OP wants (ie. auto-magically change their IP address when requesting a web page to any IP address of their choosing) and nor should they be trying to do that anyway for reasons noted in other replies below.