To make things clearer: The streaming modes require the background delivery thread (sending large files asynchronously in the background without blocking connection threads), which requires libthread and a small patch for the aolserver (extending ns_conn)
http://media.wu-wien.ac.at/download/aolserver-nsd-conn.patchThis is described in http://media.wu-wien.ac.at/download/xowiki-doc/xotcl-apm.html where the version numbers are outdated. get the actual code from cvs, not the apm packages. The file contains as well the description for installing libthread...
guess, i should move this info to oacs.org/xowiki