title: scapy WARNING: can't import layer inet: 'module' object has no attribute 'IPPROTO_IPIP
body: <p>I am using scapy with python 2.6.3 on windows 7 
  When I enter, I get a list of warnings, some less important but some like this
  "WARNING: can't import layer inet: 'module' object has no attribute 'IPPROTO_IPIP"
  when I try to send or receive packets I get errors.
  I installed following instructions and downloading files from
  <a href="http://www.secdev.org/projects/scapy/doc/installation.html#windows" rel="nofollow">http://www.secdev.org/projects/scapy/doc/installation.html#windows</a></p>
  
  <p>Can someone help me figure out what I can do to fix this bug?</p>