stsadm -o enumallwebs -includefeature: Command line error. Invalid parameter

[What you have]:
stsadm -o enumallwebs  -includefeatures gives an error: "Command line error. Invalid parameter"

[What you want]:
You want to run command similar to this
stsadm -o enumallwebs  -includefeatures -includesetupfiles -includewebparts -includeeventreceivers -includecustomlistview > enumallwebs.xml

[What you want to know]:
Description of the SharePoint Server 2007 Cumulative Update Server Hotfix Package (MOSS server-package): October 27, 2009 . Version 12.0.0.6520. includes new signature for stsadm -o enumallwebs


stsadm.exe -o enumallwebs
           [ -databasename <database name>]
           [ -databaseserver <database server name>]
           [ -includefeatures ]
           [ -includesetupfiles ]
           [ -includewebparts ]
           [ -includeeventreceivers ]
           [ -includecustomlistview ]

Using this method with additional parameters does a wonder. It shows features, setupfiles  and eventrecievers that are currently installed on the site (spweb)

It's very helpful if you are planing to migrate to 2010. The main  key of successful upgrade is to know the environment prior to it.

[What you want to do]:
To find out what's the current version of SharePoint  refer to Where to look for SharePoint version?