Again: IBM "recently" (quite a long time ago actually) introduced a bug
in XEDIT causing it to forget to release memory it acquired. LISTSERV
uses XEDIT very often to sort files, because there is no usable native
sort facility in CMS. Every time it does so, memory is allocated and not
released. You could run LISTSERV with 999M of memory and it would only
postpone its death, so the solution is to fix XEDIT. The APAR number has
been mentioned many times on this list, so it should be in the archives,
and I don't recall what it is (and it might be PE'd as well, so you might
want to check with the support centre anyway).
Eric