The installer comes as part of the Cinema4D Architecture Bundle ... i do not think it is available separately. There is a Trial verison of this bundle you can download from Maxon .. i don't know if the plugin is included in this, give that a try.
You might want to read up on this plugin a little more
over at this thread
Development of this plugin is a little .. lethargic, and the current functionality is not great. AFAIK the 'official' plugin for ArchiCAD 11 is the last one that works the way people liked it. There is an 'unofficial' plugin (link in the thread) created by some users which has similar functionality and is free (although donations via PayPal would be appreciated).
cheers,
Owen Sharp
Design Technology Manager
fjmt | francis-jones morehen thorp
iMac 27" i7 2.93Ghz | 32GB RAM | OS 10.10 | Since AC5