Forum OpenACS Q&A: Response to Virtual host installation
There are other virtual hosting/reverse proxy technologies, including Apache, SQUID, and my understanding is, various mechanisms within various ACS versions. None of these solutions would require installing the source to AOLserver.
AOLserver itself isn't bug free, and the state of the art for AOLserver is for bug fixes to be released as source patches.
I would probably not install it both ways, especially if you're new to the system. It won't hurt, but it may be confusing.