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