This is an old revision of the document!
Starting with kernel 2.6.25, zd1211rw is a mac80211 driver. As a result, the installation/patching procedure is now slightly different from what it was before. This tutorial works with kernel 2.6.27 and up. Injection on 2.6.25 and 2.6.26 requires a slightly different procedure (using compat-wireless-old).
The usual mac80211 rules apply.
See this forum thread for the details.