In this case, scrollkeeper has been replaced by rarian. Go to textproc/rarian and do (as root) 'make replace package OLDNAME=scrollkeeper' to replace scrollkeeper with rarian. This change is expresed in CHANGES but pkg_rolling-replace doesn't yet have code to extract the change and do this step automatically.
Thank you. Since this one I have solved quite a few similar replacements. Does "moved to" imply a similar problem to be solved by " make replace package OLDNAME=.." ? /editors/emacs has been moved to /editors/emacs21.