You need to do at least 1, 2 and 4 (3 may have been done already is doesn’t need to be repeated)
1.
stsadm -o activatefeature -filename IPFSSiteFeatures\feature.xml -force -url http://URLToYourSite
2.
stsadm -o activatefeature -filename IPFSWebFeatures\feature.xml –force -url http://URLToYourSite
3. You need to activate the ‘Office SharePoint Server Enterprise Site Collection features’ feature on Site Collection level.
4. iisreset