It seems that this code creates $e_rrors as a string variable, not an ns_set set. See
http://www.aolserver.com/docs/tcldev/tapi-120.htm
for docs on using ns_set. Something roughly like
set e_rrors [ns_set create]
ns_set update $e_rrors "Errors-to" "errors@rocnet.com"
might be closer to what you want to do, I think? There should be examples of this sort of usage in existing code... yes, ticket-defs.tcl does
set extra_headers [ns_set create]
ns_set update $extra_headers "Reply-to" $ticket_email
In other words, that parameter to ns_sendmail is an ns_set, it is not a string.
