ioctl() is Unix kernel's Swiss Army Knife, i.e., one kernel call to do many different things. Terrible design, btw. More info:
http://nim.cit.cornell.edu/usr/share/man/info/en_US/a_doc_lib/libs/basetrf1/ioctl32.htm and
http://www.tac.eu.org/cgi-bin/man-cgi?ioctl+2.
As far as "module blew up" I would guess that it's just a poetic sentence chosen by mod_nsd author to inform that it couldn't load the module. I wouldn't attribute too much meaning to the wording.
I recommend using pure AOLServer, unless you really need Apache for some reason. It's easy to install as Apache+mod_nsd and more stable.
