i think, i found and fixed the problem. The problem was not directly related to the xotcl-request-monitor, but to libthread (although most people install libthread for the XOTcl request monitor). The old code checked for the existence of libthread and was switching to the nicer steaming mode, when it was installed. However, bgdelivery requires as well my ns_conn patch to work (see
https://openacs.org/xowiki/weblog-portlet?ptag=bgdelivery).
Most probably you have libthread but not the patched aolserver installed. The patch for this problem is in CVS head, if you don't want to upgrade to the current xotcl-core, take the following change: http://cvs.openacs.org/cvs/openacs-4/packages/xotcl-core/tcl/chat-procs.tcl?r1=1.13&r2=1.14 If my theory is right you should have a slightly different error message as nima (something like "unknown command bgdelivery"), since bgdelivery is only created, when the patch is installed. my best guess for nima's problem is still https://openacs.org/forums/message-view?message_id=1049294.
Concerning reinstalling: the patch to the aolserver requires a compilation of the aolserver (including a "make install"). It requires a reinstallation of the aolserver, but not of your openacs instance.
