To install a feature in SharePoint 2007, do the following:
- copy the feature folder into the C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\FEATURES folder. Ensure that the feature manifest (feature.xml) exists within that folder.
- If stsadm is not in your path, open up a command prompt and navigate to C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN
- Run the command: stsadm -o installfeature -filename FeatureFolderNameHere\feature.xml (note that the path must be relative to the feature folder C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\FEATURES and cannot be full path).
- To activate the feature, run the command: stsadm -o activatefeature -filename FeatureFolderNameHere\feature.xml -url http://nameofsharepointserver
- Do an iisreset for for good measure (not sure if its actually required).