I tried to publish a project on Emacs 25.2.1 and received an arithmetic
out of range error on a call to floor.  The problem seems to be a call
to floor during the caching process that's out of the 32-bit integer range. 
Backtrace follows:

Debugger entered--Lisp error: (range-error "floor" 1549920598.0)
  floor(1549920598.0)
  org-publish-cache-ctime-of-src(<path>)
  org-publish-cache-file-needs-publishing(<path> "~/Sites/graphic-pages-production/site/" org-html-publish-to-html "~/Documents/org-mode/graphic-issue-planner/")
  org-publish-needed-p(<path> "~/Sites/graphic-pages-production/site/" org-html-publish-to-html "~/Sites/graphic-pages-production/site/" "~/Documents/org-mode/graphic-issue-planner/")
  org-publish-file(<path> ("graphic-issue-planner" :base-directory "~/Documents/org-mode/graphic-issue-planner/" :publishing-directory "~/Sites/graphic-pages-production/site/" :publishing-function org-html-publish-to-html :archived-trees nil :with-toc nil :recursive nil :headline-levels 1) t)
  org-publish-projects((("graphic-issue-planner" :base-directory "~/Documents/org-mode/graphic-issue-planner/" :publishing-directory "~/Sites/graphic-pages-production/site/" :publishing-function org-html-publish-to-html :archived-trees nil :with-toc nil :recursive nil :headline-levels 1)))
  org-publish("graphic-issue-planner")

Emacs  : GNU Emacs 25.2.1 (i686-apple-darwin, NS appkit-1038.36 Version 10.6.8 (Build 10K549))
of 2017-04-21
Package: Org mode version 9.2.1 (9.2.1-8-g1b1797-elpa @ ~/.emacs.d/elpa/org-20190211/)


Andrew Eggenberger
Editor
Lake City Graphic

office: 651-345-3316 | cell: 612-840-1578 | Twitter: @andrewlcgraphic